ATOLL RESEARCH BULLETIN 192. THE NATURAL HISTORY OF JOHNSTON ATOU, L PAUFIC OCEAN by A. Binion Jr., 4 PhBi C Shehon Tmued by THE SNITHSONIAN INSTITUTION Wdimgton, D.C., U.S.A. In Atoll Research Bulletin //I86 the names of the authors, Roger B. Clapp and William 0. Wirtz, 11, were accidently omitted from the covet^ . On the title page of #186 the publication information at the bottom should have read as it appears below. The part of this page below the dotted line may be cut out and pasted over the bottom of the title page of ij186. Issued by The Smithsonian Institution with the assistance of The Fish and Wildlife Service U.S. Department of the Interior Washington, D. C., U.S.A. February 15, 1975 In ARB 11184 a line was omitted in final typing. On page 5, in paragraph 4, line 4, after the word nesting there should be inserted 11 does occur to some extent. It was not determined if increased nest- ing". We regret the occurrence of these errors.--Eds. ATOLL RESEARCH BULLETIN NO. 192 THE NATURAL HISTORY OF JOHNSTON ATOLL, CENTRAL PACIFIC OCEAN by A. Binion Amersoi~, Jr., and Philip C. Shelton Issued by THE SMITHSONIAN INSTITUTION with t h e a s s i s t a n c e of The Fish and Wi ld l i f e Serv ice U. S. Department of t h e I n t e r i o r Washington, D. C . , U.S.A. December, 1976 ACKNOWLEDGMENT The A t o l l Research B u l l e t i n is issued by t h e Smithsonian I n s t i - t u t i o n a s a p a r t of i t s Tropica l Biology Program. It i s co- sponsored by t h e Museum of Natural History and t h e Smithsonian Press . The P res s supports and handles production and d i s t r i b u t i o n . The e d i t i n g i s done by t h e Tropica l Biology s t a f f , Botany Department, Museum of Natural His tory and by D. R, Stoddart . The B u l l e t i n was founded and t h e f i r s t 117 numbers i ssued by t h e P a c i f i c Science Board, National Academy of Sciences, with f i n a n c i a l support from t h e Off ice of Naval Research. I ts pages were l a r g e l y devoted t o r e p o r t s r e s u l t i n g from t h e P a c i f i c Science Board's Coral A t o l l Program. The s o l e r e s p o n s i b i l i t y f o r a l l s tatements made by au thor s of papers i n t h e A t o l l Research B u l l e t i n r e s t s wi th them, and statements made i n t h e Bu l l e t in do not necessa r i ly r ep resen t t h e views of t h e Smithsonian nor those of t h e e d i t o r s of t h e Bu l l e t in . Editors F. R. Fosberg M.-H.. Sachet Smithsonian I n s t i t u t i o n Washington, D. C. 20560 D. R. Stoddart Department of Geography Univers i ty of Cambridge Downing Place Cambridge, England TABLE OF CONTENTS L i s t of Figures ............................................... v L i s t of Tables .................................................. x iv .. L i s t of Appendix Tables ...................................... -xvix ......................................... In t roduct ion ........ ... 1 Physica l Environment .. . . . . . . . . . . . . . . . . . . . . ~ . . o ~ ~ . . . . . . . . . . . 3 I s l ands ........ ..................................... 3 Geology ..................................................... 7 ............................................... Geomorpholo gy 1 2 Climate .................................**..........*..... * . 15 ............................................. Temperature 15 Winds ................................................... 15 P r e c i p i t a t i o n ........................................... 18 ....................................... Rela t ive Humidity 22 Sky Cover ............................................... 22 Oceanography . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.*ae... . .o.. . . . . 24 .. Major Water Masses and Currents ......................... 24 Local Waters and Currents ............................... 26 Tides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a . . . . . . e . o . . a . . . . a 30 .. Seismic o r Tsunami Waves ................................ 30 His tory . . . . . . . . . . . . . . . . . . . . . . . . . . a e . . . . . . 9 . 3 * . . . . . o 9 e . . . . . e . . + a . 30 .. Discovery and Early Explorat ion ............................. 32 Guano Period ................................................ 34 M i l i t a r y Occupation ............. ........................... 43 Biota ........................................................... 47 P lan t s ....................................................... 4 7 Algae . . . . . . . . . . . . . . . . . . . . . . . .o . . . . . . . . . .9 . . . * . . .a . . . . . . 47 Vascular P l a n t s .....................................*..... 51 Or ig ina l F lora ..................................... 51 . Recent Vegetat ion ................................... 61 Is land account^....................^................ 62 Akau I s l a n d .................................... 62 Hikina I s l and ................................... 63 Johnston I s l and ................................ 63 . Sand I s l a n d ..................................... 65 Or ig ina l .................................... 65 Man-made .................................... 65 Inve r t eb ra t e s ........o.aa.......................a........... 65 Cnidaria (Coelenterata) ..........................a*....s 67 Molluscs. ..............................................*... 70 Annelida ................................................ 70 Arthropoda .............................................. 70 Marine ............................................... 70 T e r r e s t r i a l ......................................... 77 Medically Important Species ..................... 79 Ixodides .................................... 79 Trombiculidae ............................... 84 Rhinonyssidae ............................... 86 Mallophaga .................................. 86 Hippoboscidae ............................... 86 Echinodermata ........................................... 86 Ver tebra tes ................................................. 86 Fishes .................................................. 89 ...................................... Pe lag ic Fishes 89 ...................................... Inshore Fishes 90 ......... D i s t r i b u t i o n and Abundance Within t h e A t o l l 90 ................................. E f f e c t s of Dredging 92 ................................... Ciguater ic Fishes 103 .................................... Species Accounts 110 ....................................... Moray Eel 110 ................................... Surgeonfishes 111 Rep t i l e s ................................................ 1 1 2 .................................... Species Accounts 112 ................................ Black Sea T u r t l e 112 House Gecko ..................................... 113 ....................................... Fox Gecko 113 .................................. Mourning Gecko 113 ................................ Snake-eyed Skink 113 Birds ................................................... 1 1 4 ........................................ In t roduc t ion 116 ............................................ Seabirds 118 ........................................ Breeders 118 ................................. Former Breeders 118 ........................................ V i s i t o r s 118 .................... Waterfowl. Marsh. and Land Birds 119 ................................ Regular Migrants 119 .............................. ~ r r e g u l a r V i s i t o r s 119 ...................................... St ragg le r s 1 1 9 Accidentals ..................................... 119 ................................... In t roduct ions 119 ....................................... Annual Cycles 119 ................................. Breeding Cycles 120 ........................... Winter and Spring 120 ........................... Spring and Summer 120 Summer ...................................... 122 Summer and F a l l ............................. 122 Extended .................................... 122 Populat ion Cycles ............................... 122 Breeding Seabirds ........................... 1 2 2 Former Breeding Seabirds .................... 125 Regular Migrants ............................ 125 I r r e g u l a r V i s i t o r s . S t r agg le r s . and Accidental Birds ........................ 125 Introduced Birds ............................ 126 At-Sea Birds ................................ 126 Ef fec t s of Weather P a t t e r n s ..................... 134 ............ Ecological D i s t r i b u t i o n Within t h e A t o l l 135 Seabirds ........................................ 135 Breeding ................................ 135 .................................... V i s i t o r s 135 ................ Waterfowl. Marsh. and Land Birds 135 ............................ Regular Migrants 135 Irregular Visitors. Stragglers. and 135 Accidentals ............................. 135 ............................... Introductions 135 ................................. Island Accounts 136 ................................. Akau Island 136 ............................... Hikina Island 136 ............................. Johnston Island 136 ................................. Sand Island 137 ........................................... Mortality 139 .................... Banding and Interisland Movement 141 ......................................... Banding 141 ............................ Interisland Movement 141 ................................ Avifaunal Affinities 145 .......................................... Techniques 148 Specimens ........................................... 149 .................................... Species Accounts 151 Black-footed Albatross .......................... 151 ................................ Laysan Albatross 153 Phoenix Petrel .................................. 155 Bulwer's Petrel ................................. 155 Wedge-tailed Shearwater ......................... 165 Christmas Shearwater ............................ 178 Newell's Shearwater ............................. 187 Sooty Storm Petrel .............................. 188 Red-billed Tropicbird ........................... 188 Red-tailed Tropicbird ........................... 192 White-tailed Tropicbird ......................... 205 Blue-faced Booby ................................ 206 Brown Booby ..................................... 213 Red-footed Booby ................................ 229 Great Frigatebird ............................... 244 Lesser Frigatebird .............................. 260 Cattle Egret .................................... 260 ......................................... Pintail 262 American Wigeon ................................. 265 Northern Shoveler ............................... 266 Domestic Chicken ................................ 266 Peregrine Falcon ................................ 266 American Golden Plover .......................... 267 Black-bellied Plover ............................ 273 Semipalmated Plover ............................. 273 Bristle-thighed Curlew .......................... 274 Lesser Yellowlegs ............................... 274 Spotted Sandpiper ............................... 277 Willet 278 .......................................... Wandering Tattler ............................... 279 Ruddy Turnstone 281 ................................. Dowitcher species ............................... 286 Sanderling ..................... ................ 287 ............................... Western Sandpiper 289 P e c t o r a l Sandpiper .............................. 289 Sharp- ta i led Sandpiper .......................... 291 Buff-breasted Sandpiper ......................... 292 Ruff ............................................ 292 .............................. ~ i l s o n ' s Phalarope 293 ............................ Glaucous-winged Gul l 293 Her r ing Gu l l .................................... 294 Laughing Gul l ................................... 294 F r a n k l i n ' s Gul l ................................. 295 Gull s p e c i e s .................................... 296 Gray-backed Tern ................................ 297 Sooty Tern ...................................... 305 Elegant Tern .................................... 322 Blue-gray Noddy ................................. 322 Brown Noddy ..................................... 323 Black Noddy ..................................... 337 White Tern .................................... 345 Rock Dove ....................................... 350 Short-eared O w l ................................. 351 ......................................... Skylark 353 .............................. Japanese White-eye 354 Soc i e ty Finch ................................... 355 ................................................. Mammals 355 Spec ies Accounts .................................... 355 House Mouse ..................................... 356 Roof Rat ........................................ 358 Domestic Dog .................................... 359 .................................... Domestic C a t 360 .............................. Hawaiian Monk S e a l 361 ................................. European Rabbi t 361 ......................................... Eco log i ca l S ign i f i c ance 361 ......................... Ecologica l Values of Johnston A t o l l 361 ............. Johnston A to l l : Some Ecolog ica l Cons ide ra t i ons 362 The P l a c e of Johnston A t o l l i n t h e Na tu ra l ........................................... Biosphere 362 The Importance of Johnston A t o l l a s a S c i e n t i f i c .......................................... Laboratory 363 ........................................ Fu tu re P o t e n t i a l 364 ................... Ecologica l S i g n i f i c a n c e of Johnston A t o l l 365 .................... Johnston A to l l : Ecolog ica l S i g n i f i c a n c e 367 ......................................................... summary 369 ................................................. Acknowledgments 369 ................................................ L i t e r a t u r e Ci ted 372 ........................................................ Addendum 383 Appendix Tables 385 ................................................ LIST OF FIGURES F i g u r e 1. Efap of t h e c e n t r a l P a c i f i c Ocean. 2. Map of Johns ton A t o l l ; adap ted from Wennekens (1969) and Ashmore (1973). 3. Looking n o r t h e a s t o v e r Johns ton and Sand I s l a n d s from 3,000 f e e t , 1 2 November 1935 (U.S. Nat . Arch ives , R.G. 8 0 pho tograph) . 4 . The n o r t h e a s t end of J o h n s t o n I s l a n d a s i t appeared from t h e s o u t h i n 1923 (B.P. Bishop Museum photograph by R.S. palmer) . 5 . J o h n s t o n I s l a n d , s e e n from t h e n o r t h a t 3,500 f e e t , 1 0 October 1939 (U.S. Nat . A r c h i v e s , R.6. 8 0 pho tograph) . 6 . Looking n o r t h over Johns ton I s l a n d , 9 A p r i l 1942 (U.S. Nat. A r c h i v e s , R.G. 8 0 pho tograph) . 7 . P r o f i l e map of Johns ton I s l a n d , Johns ton A t o l l , 1923, 1942, and 1964; adap ted from Ashmore (1973) and USNOO Char t No. 5356, 20 May 1963 and 23 December 1967. 8 . Sand I s l a n d from t h e n o r t h , p r o b a b l y i n 1939 (U.S. Nat. Arch ives , R.G. 80 pho tograph) . 9 . Sand I s l a n d from t h e s o u t h e a s t , 18 March 1940; b u i l d i n g s l a t e r covered t h e e n t i r e i s l a n d , i n c l u d i n g t h e n o r t h e a s t p e n i n s u l a (U.S. Nat . A r c h i v e s , R.G. 8 0 pho tograph) . 1 0 . Sand I s l a n d a s i t appeared from t h e s o u t h e a s t abou t 1962, w i t h t h e U.S. Coast Guard LORAN S t a t i o n completed ( o f f i c i a l U.S. Coast Guard p h o t o g r a p h ) . 11. Sand I s l a n d a s i t appeared from t h e wes t , circa 1965, a f t e r 1964 c o n s t r u c t i o n had added a few a c r e s t o t h e s o u t h s i d e of t h e man-made p o r t i o n of t h e i s l a n d ( o f f i c i a l U.S. Coast Guard pho tograph) . 1 2 . Johns ton A t o l l r e e f p r o f i l e s ; adap ted from Emery (1956) and Wennekens (1969) . A: o u t e r r e e f ; B : i s o l a t e d p a t c h r e e f s . 1 3 . Sequence of s e a l e v e l changes , J o h n s t o n A t o l l (Ashmore, 1973) . f a c i n g 1 1 4 . Mean monthly a i r and s e a t e m p e r a t u r e s , Johns ton A t o l l , 1931-1972; a i r : ( s o l i d l i n e ) , d a i l y maximum and minimum ( d a s h e s ) , ext remes ( d o t s ) ; s e a : means ( b a r r e d ) . Adapted from Secke l (1962) and U.S. Department of Commerce (1972) . F i g u r e 15 . P e r c e n t f r equency of wind from E and ENE (open b a r ) and ESE and NE ( s t i p p l e d b a r ) , J o h n s t o n A t o l l . 17 1 6 . Mean monthly wind speed , J o h n s t o n A t o l l , 1931-1972; means ( s o l i d l i n e ) , upper ex t remes ( d o t s ) . Adapted from U.S. Department of Commerce (1972) . 17 17. J o h n s t o n A t o l l mean U components; adap ted from J o i n t Task Force Seven (1959). 1 9 1 8 . J o h n s t o n A t o l l mean V components; a d a p t e d from J o i n t Task Force Seven (1959). 1 9 1 9 . Mean monthly p r e c i p i t a t i o n , J o h n s t o n A t o l l , 1931-1972; means ( s o l i d l i n e ) , ext remes ( d o t s ) , Adapted from U.S. Department of Commerce (1972). 2 0 20. Mean monthly r e l a t i v e humid i ty , J o h n s t o n A t o l l , 1931- 1972; 0100 h o u r s ( d o t s ) , 0700 h o u r s ( d a s h e s ) , 1300 h o u r s ( s o l i d l i n e ) , 1900 h o u r s ( b a r r e d ) . Adapted from U.S. Department of Commerce (1972) . 21 21. Mean monthly sky c o v e r , s u n r i s e t o s u n s e t , Johns ton A t o l l , 1931-1972. Sky cover i s e x p r e s s e d i n a r ange of 0 t o 3 a s b e i n g c l e a r , 4 t o 7 p a r t l y c loudy , and 8 t o 1 0 c loudy. Adapted from U.S. Department of Commerce (1972). 22. Mean monthly number of days of c l e a r s k i e s ( s o l i d l i n e ) , p a r t l y c loudy s k i e s ( d o t s ) , c loudy s k i e s ( b a r r e d ) , and p r e c i p i t a t i o n of 0 .01 i n c h o r more ( d a s h e s ) , Johns ton A t o l l , 1931-1972. Adapted from U.S. Department of Commerce (1972). 23 23. P a c i f i c Ocean c u r r e n t s (King, 1 9 6 7 ) . 25 24. Seasona l and t i d a l f low reg imes , J o h n s t o n Atoll. (Wennekens, 1969) . 25. J o h n s t o n A t o l l i n f e r r e d lagoon c i r c u l a t i o n , January- February 1965 (Kopenski and Wennekens, 1.966). 28 26. Johnston A t o l l i n f e r r e d lagoon c i r c u l a t i o n and t u r b i d o u t f l o w ( w e s t e r l y f l o w ) , July-August 1965 (Kopenski and Wennekens , 1966) . 29 27. J o h n s t o n A t o l l i n f e r r e d c i r c u l a t i o n and t u r b i d o u t f l o w ( e a s t e r l y f l o w ) , July-August 1965 (Kopenski and Wenne- kens , 1966) . 2 9 28. T i d a l wave r e c o r d s , Johns ton A t o l l (Wennekens, 1969) . 3 1 F i g u r e 29. Algae c o l l e c t i o n s t a t i o n s , J o h n s t o n A t o l l , 1965-1966 (Buggeln and Tsuda, 1969) . 30. D i s t r i b u t i o n of t h e f i v e most i m o o r t a n t p l a n t s p e c i e s on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , Johns ton A t o l l , July-August 1963. 31. D i s t r i b u t i o n of dominant p l a n t s p e c i e s on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , Johns ton A t o l l , May 1967. 32. J o h n s t o n A t o l l showing i n v e r t e b r a t e and f i s h c o l l e c t i o n s t a t i o n s , dredged a r e a s , and t h e e x t e n t of s i l t l a d e n w a t e r (Brock, et a t . , 1966) . 33. D i s t r i b u t i o n of p o s i t i v e samples of Ornithodoros capensis f o r 1965, Sand I s l a n d , J o h n s t o n Atoll . . I n s e r t s show bi-monthly i n f e s t a t i o n r a t e s f o r t h e t h r e e major a r e a s . 34 . Bi-monthly t i c k i n f e s t a t i o n r a t e s ( s t i p p l e s ) compared w i t h b r e e d i n g b i r d p o p u l a t i o n f l u c t u a t i o n s ( b a r s ) , Sand I s l a n d , J o h n s t o n A t o l l , 1965. 35. Areas used by Sooty Terns and Wedge-tailed Shearwate r s on Sand I s l a n d , Johns ton A t o l l , 1965. 36. F i s h c o l l e c t i o n s t a t i o n s , Johns ton A t o l l , 1963-1964 (Brock, et a t . , 1965) . 37. Breeding c y c l e s of s e a b i r d s a t J o h n s t o n A t o l l ; s t i p p l e d a r e a r e p r e s e n t s eggs , b a r r e d a r e a young, and h l a c k d o t s non-breeding b i r d s . 38. Monthly cumula t ive b i r d p o p u l a t i o n s , Johns ton A t o l l , 1963-1969. 39. Monthly mean s h o r e b i r d p o p u l a t i o n s f o r Johns ton A t o l l , 1963-1969; Golden P lover ( s o l i d l i n e ) , Ruddy Turns tone ( d o t s ) , Wandering T a t t l e r (dashes ) . 40. D i u r n a l b i r d p o p u l a t i o n s a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 41. Monthly d i u r n a l p o p u l a t i o n f l u c t u a t i o n s w i t h i n t h e a t - s e a g r i d by s p e c i e s group, 1963-1967. 42. T o t a l n o c t u r n a l b i r d s i g h t i n g s a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 43. N e s t i n g a r e a s of ground nest in^ b i r d s ( excep t Sooty Terns ) on t h e - o r i g i n a l p o r t i o n of sand I s l a n d , ~ o h n s t o n Gall, 1963. F i g u r e 44. Nes t ing a r e a s of b i r d s which normal ly n e s t i n low v e g e t a t i o n on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , Johns ton A t o l l , 1963. 45. Bulwer ' s P e t r e l c h i c k , abou t 2 months o l d , i n f r o n t of r o c k c r e v i c e n e s t s i t e a l o n g causeway, Sand I s l a n d , Johnston A t o l l , 25 August 1966 (POBS? pho to by P.C. She l ton) . 46. Concre te s l a b s on e a s t s h o r e , a t base of n o r t h e a s t p e n i n s u l a , Sand I s l a n d , J o h n s t o n A t o l l , 8 May 1967. Chr i s tmas Shearwate r s n e s t e d r e g u l a r l y under t h e l a r g e s l a b s a t l e f t , and Bulwer ' s P e t r e l s a t t e m p t e d t o n e s t a t l e a s t once under t h e s l a b s i n c e n t e r of p h o t o . Brown Noddies n e s t e d i n t h e edge of t h e Sesuviwn growing j u s t above t h e s to rm beach (POBSP pho to by P.C. S h e l t o n ) . 47. D i s t r i b u t i o n of Bulwer ' s P e t r e l n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969. 48. Means and ex t remes of semimonthly e s t i m a t e s of Bulwer ' s P e t r e l numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969. 49. D i u r n a l o c c u r r e n c e of Bulwer ' s P e t r e l s a t s e a 175 m i l e s southwest of Johns ton Atol l . , 1963-1967. 50. D i s t r i b u t i o n of Wedge-tai led Shearwater n e s t s i t e s on Sand I s l a n d , J o h n s t o n A t o l l , 1963-3969. Numhers i n d i - c a t e c h i c k s banded i n 1968. 51. Wedge-tailed Shearwater c h i c k i n f r o n t of burrow under Lep tu rus r e p e z s c lumps, Sand I s l a n d , Johns ton A t o l l , 2 September 1966 (POBSP pho to by P.C. S h e l t o n ) . 52. Wedge-tailed Shearwate r s among Tr'ribuZus, Boerhavia, and L e p t u r u s on sou thwes t Sand I s l a n d , Johns ton A t o l l , mid- morning J u l y 1963 (POBSP p h o t o by A . B . Amerson, J r . ) . 53. Means and ex t remes of semimonthly e s t i m a t e s o f Idedge- t a i l e d Shearwater numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. 54. D i u r n a l o c c u r r e n c e of Wedge-tai led Shearwate r s ( l i s h t phase) a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 55. Chr i s tmas Shearwate r c h i c k , 2 and 1 / 2 months o l d , i n s h a l l o w t r e n c h burrow under L e p t u r u s r e p e n s clump on e a s t s h o r e of Sand I s l a n d , J o h n s t o n A t o l l , 29 August 1966 (POBSP photo by P.C. S h e l t o n ) . F i g u r e 56. Chr i s tmas Shearwater c h i c k , 2 months o l d , and a d u l t s i n bunker on e a s t s h o r e , Sand I s l a n d , Johns ton A t o l l , 1 September 1966 (POBSP pho to by P.C. S h e l t o n ) . 57. D i s t r i b u t i o n of Chr i s tmas Shearwater n e s t sites, Sand I s l a n d , Johns ton A t o l l , 1963-1969. 58. Means and ex t remes of semimonthly e s t i m a t e s of Chr i s tmas Shearwater numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964- 1969. 59. D i s t r i b u t i o n of Red- ta i l ed T r o p i c b i r d n e s t s on Sand I s l a n d , Johns ton A t o l l , 1967. 60. D i s t r i b u t i o n of Red-tail.ed T r o p i c b i r d n e s t s on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , 1969. 61. D i s t r i b u t i o n of R e d - t a i l e d T r o p i c b i r d n e s t s on t h e man- made p o r t i o n of Sand I s l a n d , Johns ton A t o l l , 1969. 62. Red- ta i l ed T r o p i c b i r d on n e s t under T o u m e f o r t i a bush n o r t h e a s t of t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , Johns ton A t o l l , 25 February 1967 (POBSP pho to by P.C. S h e l t o n ) . 63. Looking e a s t from t o p of power b u i l d i n g , Sand I s l a n d , Johns ton A t o l l , 5 September 1969. S e v e r a l Red- ta i l ed T r o p i c b i r d s n e s t e d under t h e s e Ptuchea odorata bushes (POESP pho to by P.C. S h e l t o n ) . 64. Means of semimonthly e s t i m a t e s of Red- ta i l ed T r o p i c b i r d numbers, Sand I s l a n d , J o h n s t o n A t o l l ; 1965-1966 ( s o l i d l i n e ) compared w i t h 1967-1969 ( d o t s ) . 65. Means of semimonthly e s t i m a t e s of Red- ta i l ed T r o p i c b i r d numbers, Johns ton I s l a n d , J o h n s t o n A t o l l ; 1965-1966 ( s o l i d l i n e ) compared w i t h 1967-1969 ( d o t s ) . 66 . D i u r n a l o c c u r r e n c e of R e d - t a i l e d T r o p i c b i r d s a t s e a 175 m i l e s sou thwes t of J o h n s t o n A t o l l , 1963-1967. 67. Blue-faced Booby a d u l t and c h i c k , J o h n s t o n A t o l l , J u l y 1923 (B.P. Bishop Museum pho to) . 68. A r o o s t i n g c l u b of Blue-faced Boobies on Sand I s l a n d , J o h n s t o n A t o l l , 2 J u n e 1 9 4 1 (U.S. N a t i o n a l A r c h i v e s , R.G. p h o t o ) . 69. Means and ex t remes of semimonthly e s t i m a t e s of Blue- f a c e d Booby numbers, Sand I s l a n d , Johns ton A t o l l , 1963- 1969. F i g u r e 70. D i s t r i b u t i o n of Brown Booby n e s t s on Sand I s l a n d , Johns ton A t o l l , 1969. 71. Brown Boobies i n e a r l y s t a g e s o f c o u r t s h i p and n e s t b u i l d i n g , e a s t h i l l of Sand I s l a n d , J o h n s t o n A t o l l , 25 February 1969. V e g e t a t i o n i s m o s t l y Roerhavia w i t h s c a t t e r e d clumps of Tribulus (POBSP photo by P.C. S h e l t o n ) . 72. Brown Booby a d u l t s and 31-day-old c h i c k , west s h o r e of n o r t h e a s t p e n i n s u l a , Sand I s l a n d , Johns ton A t o l l , 9 J u l y 1966. Brown Noddies r o o s t and n e s t h e r e a l s o ; Sooty Terns are i n t h e background (POBSP pho to by P.C. S h e l t o n ) . 215 73. Means and extremes of semimonthly e s t i m a t e s of Brown Booby numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. 216 74. D i s t r i b u t i o n of Red-footed Booby n e s t s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1967. 231 75. Means and extremes of semimonthly e s t i m a t e s of Red- f o o t e d Booby numbers, Sand ~ s l a n d , Johns ton A t o l l , 1964- 1969. 233 76. Four Red-footed Boobies n e s t i n g on a r t i f i c i a l p l a t f o r m s (framework of a n o l d b o a t ) on t h e s o u t h e a s t beach of Sand I s l a n d , Johns ton A t o l l , 5 May 1969 (POBSP photo by P.C. S h e l t o n ) . 236 77. Red-footed Booby n e s t p l a c e d o n ground on c r e s t of h i l l e a s t of t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , Johns ton A t o l l , 4 May 1969. Subadul t Blue-faced Booby r o o s t i n g a t lower r i g h t ; Sooty Tern a d u l t s and c h i c k s and Brown h'oddy a d u l t nea rby (POBSP p h o t o by P.C. S h e l t o n ) . 78. D i u r n a l o c c u r r e n c e of Red-footed Boobies a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 79. G r e a t F r i g a t e b i r d n e s t i n g a r e a s , Sand I s l a n d , Johns ton A t o l l , 1963-1969. 80. Grea t F r i g a t e b i r d s n e s t i n g on ground on c r e s t of h i l l e a s t of t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , Johns ton A t o l l , May o r June 1964. Sooty Tern a d u l t s and c h i c k s surround t h e co lony (POBSP photo by A . B . Amerson, J r . ) . 247 81. G r e a t F r i g a t e b i r d colony on s o u t h s h o r e , Sand Ts land , Johns ton Atoll. , 26 February 1969 (POBSP photo by P.C. S h e l t o n ) . 247 F i g u r e 82. G r e a t F r i - g a t e b i r d r o o s t i n g a r e a s , Sand I s l a n d , Johnston A t o l l , 1963-1969. 83 . Cleans and ex t remes of semimonthly e s t i m a t e s of G r e a t F r i g a t e b i r d numbers, Sand I s l a n d , 3ohns ton A t o l l , 1963-1969. 84. D i u r n a l o c c u r r e n c e of Grea t F r i g a t e b i r d s a t sea 175 miles sou thwes t of Johns ton A t o l l , 1963-1967. 85 . Moving a v e r a g e s of semimonthly e s t i m a t e s of Golden P l o v e r s , Sand and Johns ton I s l a n d s combined, 1963- 1969. 86 . D i s t r i b u t i o n of Golden P l o v e r s on Sand I s l a n d , Johns ton A t o l l , 26 December 1965. 87 . Moving a v e r a g e s of semimonthly e s t i m a t e s of L7andering T a t t l e r s , Sand and Johns ton I s l a n d s combined, 1963- 1969. 88. Moving a v e r a g e s of semimonthly e s t i m a t e s of Ruddy Turn- s t o n e s , Sand I s l a n d , Johns ton A t o l l , 1963-1969. 89. Dowitcher s p e c i e s photographed on Sand I s l a n d , Johns ton A t o l l , 8 September 1969 (POBSP photo by P.C. S h e l t o n ) . 90. Moving a v e r a g e s of semimonthly e s t i m a t e s of S a n d e r l i n g s , Sand and J o h n s t o n I s l a n d s , 1963-1969. 91. D i s t r i b u t i o n of Gray-backed Tern n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1966. 92. D i s t r i b u t i o n of Gray-backed Tern n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1967. 93. Gray-backed Tern on n e s t ( c e n t e r fo reground) among Sooty Terns i n Ipomoea and Lepi5u.m~ on s o u t h s h o r e of Sand I s l a n d , Johns ton A t o l l , 2 1 A p r i l 1969 (POBSP pho to by P.C. She l ton) . 94. Gray-backed Tern n e s t i n g a r e a on southkles t i s l e t , Sand I s l a n d , Johns ton A t o l l , 1 6 A p r i l 1969. Two a d u l t s , one c h i c k , and f o u r eggs a r e shown (POBSP p h o t o by P . C . S h e l t o n ) . 95. Means and ex t remes of semimonthly e s t i m a t e s of Gray-backed Tern numbers, Sand I s l a n d , Johns ton A t o l l , 1964-1969. 302 F i g u r e 96. Sooty Terns ( t i n y d o t s ) u t i l i z e a lmost a l l a v a i l a b l e ground n e s t s i tes on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , May 1964 (mosaic by A.B. Amerson, J r . , from POBSP photographs t a k e n a t t h e 620-foot tower l e v e l by R,TJ. M e r r i l l ) . 97. Sooty Tern n e s t i n g a r e a s , Sand I s l a n d , Johns ton A t o l l , 1967. 98. N e s t i n g Sooty T e r n s cover v i r t u a l l y t h e e n t i r e south- west p o r t i o n of Sand I s l a n d , Johns ton A t o l l , 1 5 A p r i l 1969. Hos t of t h e Wedge-tailed Shearwater burrows a r e under t h e Lep tu rus i n t h i s a r e a . The sou thwes t i s le t and o l d dock are v i s i b l e a t upper l e f t (POBSP photo by P.C. S h e l t o n ) . 99. N e s t i n g Sooty T e r n s n o r t h e a s t of t h e t r a n s m i t t e r b u i l d i n g and on t h e n o r t h e a s t p e n i n s u l a , Sand I s l a n d , Johns ton A t o l l , 3 0 March 1967 (POBSP pho to by P.C. She l ton) . 100. Means and extremes of semimonthlv e s t i m a t e s of a d u l t Sooty Tern numbers, Sand I s l a n d , Johns ton A t o l l , 1963- 1969. 101. Means of semimonthly estimates of Sooty Tern eggs and yourig, Sand I s l a n d , Johns ton A t o l l , 1963-1969. 102. I n t e r i s l a n d movement of Sooty Terns i n v o l v i n g t h e Hawaiian I s l a n d s , Johns ton A t o l l , and Wake A t o l l (Gould, 1974b) . 103. D i u r n a l o c c u r r e n c e of Sooty T e r n s a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 104 . Orange-streamered Sooty T e r n s a t s e a 175 miles sou thwes t of Johns ton A t o l l , 1963-1967. 105. Noc tu rna l o c c u r r e n c e o f Sooty Terns a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. 106. Brown Noddy n e s t d i s t r i b u t i o n , Sand I s l a n d , Johns ton A t o l l , A p r i l 1967. 107 , Brown Noddies and Sooty T e r n s on t h e sou thwes t p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , J u l y 1923. J o h n s t o n I s l a n d i s v i s i b l e i n t h e background (B.P. Bishop Museum photo by Chapman G r a n t ) . 108. Brown Noddies n e s t i n g and r o o s t i n g on t h e sou thwes t i s le t , Sand I s l a n d , J o h n s t o n A t o l l , 9 May 1967 (POBSP photo by P.C. S h e l t o n ) . 109 . Means and extremes of semimonthly e s t i m a t e s of Brown Noddy numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1969. 110. Black Noddy n e s t i n g and r o o s t i n g a r e a s , Sand I s l a n d , Johns ton A t o l l , 1963-1967. 111. Black Noddy n e s t i n Amaranthus p l a n t s s o u t h of t h e t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , 7 May 1967. Sooty Tern a d u l t s and c h i c k s nea rby (POBSP photo by P.C. S h e l t o n ) . 112 . Black Noddy n e s t w i t h 12-day-old c h i c k i n Amaranthus p l a n t s o u t h of t h e t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , Johns ton A t o l l , 4 J u n e 1969 (POBSP pho to by P.C. S h e l t o n ) . 113. Means and extremes of semimonthly e s t i m a t e s of Black Noddy numbers, Sand I s l a n d , Johns ton A t o l l , 1964-1969. 114. White T e r n s r o o s t i n g on u n d e r c u t beach r o c k on s h o r e of Johns ton I s l a n d , .Johnston A t o l l , J u l y 1923 (B.P. Bishop Museum p h o t o ) . 115. White Tern c h i c k h a t c h e d on framework of o l d r a d i o t e l e s c o p e , Johns ton I s l a n d , J o h n s t o n A t o l l , 1 9 June 1969 (POBSP photo by P.C. S h e l t o n ) . 116 . Means and ex t remes of semimonthly e s t i m a t e s of d i u r n a l White Tern numbers, J o h n s t o n A t o l l , 1963-1969. 117. D i u r n a l o c c u r r e n c e of T%%ite T e r n s a t s e a 175 m i l e s sou thwes t of Johns ton A t o l l , 1963-1967. LIST OF TABLES Tab le Page - Ownership and c o n t r o l of Johns ton A t o l l (adapted from Bauer , 1965) . D i s t r i b u t i o n of b e n t h i c mar ine a l g a e a t Johns ton A t o l l . Vascu la r p l a n t s known from Johns ton A t o l l . C n i d a r i a ( C o e l e n t e r a t a ) from Johns ton A t o l l . D i s t r i b u t i o n and abundance of c o r a l s a t Johns ton A t o l l , 1964-1965. D i s t r i b u t i o n and abundance of Mol lusca from Johns ton A t o l l . Annel ida from J o h n s t o n A t o l l . Marine Arthropoda from Johns ton A t o l l . I n s e c t s r e c o r d e d from Johns ton A t o l l ; adap ted from Chi l son (1953) . B e r l e s e sample da ta - -0 rn i thodoros c a p e n s i s i n f e s t a t i o n r a t e s f o r Sand I s l a n d , Johns ton A t o l l , 1965. Berlese sample data--bimonthly O r n i t h o d o r o s c a p e n s i s i n f e s t a t i o n r a t e s f o r Sand I s l a n d , Johns ton A t o l l , 1.965. Orn i thodoros c a p e n s i s i n f e s t a t i o n r a t e s from B e r l e s e samples of h o s t s ' n e s t s . Mallophaga c o l l e c t e d a t Sand I s l a n d , .Johnston A t o l l by t h e POBSP; adap ted from Amerson and Emerson (1971). Echinodermata from Johns ton Atol l . I n s h o r e f i s h e s recorded from Johns ton A t o l l . T o x i c i t y of f i s h s p e c i e s t e s t e d f o r c i g u a t e r a a t Johns ton A t o l l . B i r d s from J o h n s t o n A t o l l . S t a t u s of b i r d s on Johns ton A t o l l . Peak b r e e d i n g p e r i o d of Johns ton A t o l l b i r d s . Nonthly o c c u r r e n c e of non- res iden t b i r d s a t Johns ton A t o l l . Table 21. Occurrence of b i r d s a t s e a i n t h e g r i d 175 miles southwest of Johns ton A t o l l . S t a t u s and a r e a of d e r i v a t i o n of b i r d s observed a t s e a n e a r Johns ton A t o l l . Sooty Tern m o r t a l i c y from guywire s t r i k e s , Sand I s l a n d , March-July 1965. B i r d s banded a t Johns ton A t o l l , 1963 t o 1973. Year ly band r e t u r n t o t a l s f o r Johns ton A t o l l . I n t e r i s l a n d movement of banded b i r d s i n v o l v i n g Johns ton Atoll. B i r d specimens and summary of new r e c o r d s from Johns ton A t o l l . P r o d u c t i v i t y of Bulwer ' s P e t r e l s on Sand I s l a n d , Johns ton A t o l l , 1964-1969. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Bulwer ' s P e t r e l s on Sand I s l a n d , 1964-1969. Banding and r e c a p t u r e s of Bulwer 's P e t r e l s , Sand I s l a n d , Johns ton A t o l l , 1964-1969. P r o d u c t i v i t y of Wedge-tailed Shearwate r s on Sand I s l a n d , Johns ton A t o l l , 1963-1968. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Wedge-tai led Shearwate r s , Sand I s l a n d , Johns ton A t o l l , 1963-1969. Banding and r e c a p t u r e s of Wedge-tai led S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. P r o d u c t i v i t y of Chr i s tmas Shearwate r s on Sand I s l a n d , Johns ton A t o l l , 1963-1969. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Chr i s tmas S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. Banding and r e c a p t u r e s of Chr i s tmas S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. D i s t r i b u t i o n and n e s t i n g s u c c e s s of R e d - t a i l e d T r o p i c b i r d s by h a b i t a t t y p e , Sand and Johns ton I s l a n d s , 1967-1969. T a b l e 38 . P r o d u c t i v i t y of Red- ta i l ed T r o p i c b i r d s on Johns ton A t o l l , 1964-1969. I n c u b a t i o n and f l e d g i n g p e r i o d of Red- ta i l ed T r o p i c b i r d eggs and c h i c k s , Sand I s l a n d , J o h n s t o n A t o l l , 1967-1969. Banding and r e c a p t u r e of R e d - t a i l e d T r o p i c b i r d s , Sand and Johns ton I s l a n d s , 1963-1973. S i g h t i n g s of Whi te - t a i l ed T r o p i c b i r d s on Johns ton A t o l l . Semimonthly p o p u l a t i o n e s t i m a t e s of Blue-faced Boobies on Sand I s l a n d , Johns ton A t o l l , 1963-1969. Blue-faced Boobies banded on Sand I s l a n d , Johns ton A t o l l , by t h e POBSP. P r o d u c t i v i t y of Brown Boobies , Sand I s l a n d , Johns ton A t o l l , 1963 th rough 1969. Success r a t e s of d i f f e r e n t c l u t c h s i z e s of Brorm Boobies , Sand I s l a n d , Johns ton A t o l l , 1964 th rough 1969. P e r c e n t a g e s of Brorm Eooby c h i c k s r e s u l t i n g from one, two, and t h r e e egg c l u t c h e s , Sand I s l a n d , Johns ton A t o l l , 1964 th rough 1969. R e n e s t i n g a t t e m p t s , i n c i d e n c e s of two c h i c k s r e a r e d i n one n e s t , and number of c h i c k s r a i s e d by f o s t e r p a r e n t s o r by hand, Sand I s l a n d , Johns ton A t o l l , 1964 th rough 1969. P e r c e n t of Brown Booby c h i c k s produced and s u c c e s s r a t e s of n e s t s by th i . rds of b r e e d i n g s e a s o n s , Sand I s l a n d , J o h n s t o n A t o l l , 1964 t h r o u g h 1969. N e s t i n g s u c c e s s of known-age Brorvn Boobies, Sand I s l a n d , Johns ton A t o l l . Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Brown Booby b r e e d i n g c y c l e , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969. Xumber of Brown Booby n e s t s e s t a b l i s h e d by semimonthly p e r i o d s , Sand I s l a n d , Johnston A t o l l , 1964-1969. Banding and r e c a p t u r e s of Brown Boobies , Sand I s l a n d , Johns ton A t o l l , 1963-1969. P r o d u c t i v i t y of Red-footed Boobies , Sand I s l a n d , Johns ton A t o l l , 1963-1969. Table 54. Known a g e Red-footed Booby n e s t i n g , Sand I s l a n d , Johnston A t o l l , 1963-1969. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Red-footed Booby b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1969. Plumage r a t i o s of Red-footed Boobies , Sand I s l a n d , J o h n s t o n A t o l l , 1967. Banding and r e c a p t u r e s of Red-footed Boobies , Sand I s l a n d , Johns ton A t o l l , 1963-1973. P r o d u c t i v i t y of Great F r i g a t e b i r d s , Sand I s l a n d , Johns ton A t o l l , 1963-1967. F a t e o f young Grea t F r i g a t e b i r d s banded on Sand I s l a n d , J o h n s t o n A t o l l , 1963-1967. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Grea t P r i g a t e - b i r d b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1969. Plumage r a t i o s of Grea t F r i g a t e b i r d s , Sand I s l a n d , Johns ton A t o l l . O b s e r v a t i o n s of P i n t a i l s on Johns ton A t o l l . O b s e r v a t i o n s of B r i s t l e - t h i g h e d Curlews on Sand I s l a n d , Johns ton A t o l l , 1.963-1969. Numbers and p e r c e n t a g e s of Ruddy T u r n s t o n e s s i g h t e d on J o h n s t o n A t o l l t h a t were color-marked on S t . George I s l a n d , P r i b i l o f s , F a l l 1966. O b s e r v a t i o n s of P e c t o r a l Sandp ipers o n Sand I s l a n d , Johns ton A t o l l , 1963-1968. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Gray-backed Tern b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. Nark- re lease - recap tu re c a l c c l a t i o n s of Sooty Tern b r e e d i n g p o p u l a t i o n s , Sand I s l a n d , J o h n s t o n A t o l l , based on February- A p r i l 1967 r e c a p t u r e s . Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Sooty T e r n s , Sand I s l a n d , Johns ton A t o l l , 1.963-1969. Orange-streamered Sooty Tern s i g h t i n g s w i t h i n a 50-mile- r a d i u s of Johns ton Atoll . and i n t h e a t - s e a g r i d :I75 miles sou thwes t of Johns ton A t o l l , 1964-1967. Table 70. Nest ing m a t e r i a l used by Brown Noddies, Sand I s l a n d , Johnston A t o l l ; obse rva t i ons by B.A. Har r ing ton , about 327 1 Play 1968. 71. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Brown Noddy breeding c y c l e s , Sand I s l a n d , Johnston A t o l l , 1964-1969. 334 72. Dai ly egg l a y i n g , ha t ch ing , and l o s s e s f o r Brown Noddies, Sand I s l a n d , Johnston A t o l l , July-September, 1964-1969. 73. Known-age Brown Noddy r e c a p t u r e s taken from eggs o r ch i cks , Sand I s l a n d , Johnston A t o l l , 1967. 74. Primary molt s c o r e s of Brown Noddies, Sand I s l a n d , Johnston A t o l l . 75. Nest ing succes s of Black Noddies on Sand I s l a n d , Johnston A t o l l , 1963-1969. 76. C a l c u l a t i o n s of numbers of Black Noddies u s ing Sand I s l a n d , Johnston A t o l l , 1967. 77. Primary molt s c o r e s of Black Noddies caught r o o s t i n g on Sand I s l a n d , Johnston A t o l l , February-April 1967. 78. Extreme d a t e s of s i g n i f i c a n t even t s i n t h e Black Noddy breeding c y c l e s , Sand I s l a n d , Johnston A t o l l , 1964-1969. 79. Observat ions of Short-eared Owls on Johnston A t o l l . 80. Records of Japanese White-eyes on Johnston A t o l l . 81. D i s t r i b u t i o n and s t a t u s of mammals a t Johnston A t o l l . 82. Breeding cond i t i on of house mice au tops i ed , October 1964- March 1965. 83. Evidence of breeding c o n d i t i o n i n house mice l ive- t rapped and r e l e a s e d , October 1966 and February 1967. LIST OF APPENDIX TABLES Appendix Table 1. POBSP personnel p a r t i c i p a t i n g i n b i r d s t u d i e s on Johnston A t o l l , J u l y 1963-September 1969. 2 . Annotated l i s t of vascular plant ' spec ie s recorded from Akau I s l and , Johnston A t o l l . 3 . Annotated l i s t of vascular p l a n t spec ie s recorded from Hikina I s l and , Johnston A t o l l . 4 . Annotated l i s t of vascular p l an t spec ie s recorded from Johnston I s l and , Johnston A t o l l . 5. Annotated l i s t of vascular p l an t spec ie s recorded from t h e man-made por t ion of Sand I s l and , Johnston A t o l l . 6 . Annotated l i s t of vascular p l an t spec ie s recorded from t h e o r i g i n a l po r t ion of Sand I s l a n d , Johnston A t o l l . 7 . Bird specimens c o l l e c t e d on Johnston A t o l l . 5. Pre-POBSP observa t ions of Sooty Terns on Johnston A t o l l . .JOHNSTON ATOLL Figure 1. Map of the central Pacific Ocean. TIIE NATURAI, HISTORY OF JOI-INSTON ATOLL, CENTRAL PACIFIC OCEAN 11y A. Ui11io11 Amerson, Jr., and Philip C. Sl~elton INTRODUCTION Johnston A t o l l c o n s i s t s of two highly modified n a t u r a l i s l a n d s and two completely man-made i s l a n d s t o t a l i n g about a square mi l e i n su r face a rea ly ing on a 14 by 7 mi l e c o r a l reef platform i n t h e t r o p i c a l P a c i f i c Ocean a t 16'45'N, 16g031'W (Figure 1 ) . The n e a r e s t land i s French F r i g a t e Shoals i n t h e northwestern Hawaiian I s l a n d s , about 450 n a u t i c a l m i l e s north-northwest; Honolulu, Hawaii i s 717 nm northwest; t h e Marshal l I s l a n d s l i e almost 1,200 nm southwest, Howland I s l and is 1,050 nm south- southwest, and Kingman Reef i n t h e Line I s l a n d s i s about 850 nm southeas t . Although t h e a t o l l was discovered i n 1796 and claimed by the United S t a t e s i n 1858, i t was uninhabited except f o r b r i e f v i s i t s by guano miners , adventurers , government s c i e n t i s t s and m i l i t a r y personnel u n t i l 1936, when t h e U . S . Navy began developing f i r s t a seaplane base and l a t e r an a i r s t r i p and r e f u e l i n g f a c i l i t i e s which served a s an important l i n k from t h e Hawaiian I s l a n d s t o t h e western P a c i f i c dur ing World War 11. After t h e war, opera t ions diminished u n t i l t h e l a t e 1950's when t h e a t o l l was used f o r atmospheric nuclear t e s t i n g . Although t h e l a s t t e s t s were executed i n 1962, f a c i l i t i e s have been maintained " . . . for re - suming nuclear t e s t i n g i n t h e P a c i f i c Ocean should t h e Test Ban Treaty of 1963 be abrogated by a fo re ign world power" (Bauer, 1965: 1 ) . Most r e c e n t l y t h e a t o l l has become t h e s to rage s i t e f o r obsole te chemical warfare agen t s , including nerve gas formerly s tored on Okinawa, and he rb ic ides used i n southeas t Asia. The a t o l l was made a f e d e r a l b i rd refuge by executive order of Pres ident Calvin Coolidge i n 1926. This order remains i n e f f e c t , a l though 11 Paper Number 80, P a c i f i c Ocean Biologica l Survey Program, Smithsonian - I n s t i t u t i o n , Washington, D.C. 21 Present address: Department of Systematics and Ecology, The Univers i ty - of Kansas, Lawrence, Kansas 66045 31 Present address: Department of Biology, Clinch Valley College, Wise, - Virg in ia 24293 subsequent executive orders have given primary j u r i s d i c t i o n over t h e a t o l l t o m i l i t a r y agencies , f i r s t t o t h e Navy, l a t e r t o t h e U.S. A i r Force. P resen t ly a J o i n t Task Force has j u r i s d i c t i o n over a l l t h e a t o l l except f o r Sand I s l and , which is t h e s i t e of a U.S. Coast Guard LORAN s t a t i o n . The a t o l l i s an unincorporated t e r r i t o r y (=possession) of t h e United S ta t e s . This i s d is t inguished from an incorporated t e r r i t o r y ( = t e r r i t o r y ) i n t h a t i t i s " . . . t e r r i t o r y t o which t h e c o n s t i t u t i o n [of t h e United S t a t e s ] has not been express ly and f u l l y extended" (U.S. Department of S t a t e , 1965: 9) . Although t h e oceanic reg ion i n which Johnston A t o l l l i e s i s r e l a - t i v e l y unproductive, l i f e i s abundant on the a t o l l i t s e l f . A t l e a s t ha l f a m i l l i o n seab i rds use t h e a t o l l f o r roos t ing and nes t ing . Most of t h e s e a r e of one spec ie s , Sooty Tern (Sterna fuscata), but t h e t o t a l known avifauna i s 56 spec ie s , inc luding 12 r egu la r breeders and half-a-dozen r egu la r migrants. Other t e r r e s t r i a l forms a r e sca rce , and a r e l imi t ed mainly t o introduced spec ie s , including f i v e spec ie s each of mammals and r e p t i l e s , a l l of which were introduced, a t l e a s t 87 spec ie s of i n s e c t s , many of which were introduced, and we l l over one hundred spec ie s of p l a n t s , only t h r e e of which a r e na t ive . The inshore marine b i o t a i s r i c h e r . To d a t e 194 spec ie s of inshore f i s h e s have been recorded, s ea t u r t l e s v i s i t t h e a t o l l r e g u l a r l y i n small numbers, porpoises a r e occas ional ly seen ou t s ide t h e lagoon, and i n 1968 and 1969 Hawaiian Monk Sea l s v i s i t e d t h e i s l a n d s f o r t h e f i r s t time so f a r a s is known. Trop ica l marine i n v e r t e b r a t e s a r e abundant i n t h e lagoon. M i l i t a r y occupation and cons t ruc t ion during t h e p a s t 40 yea r s have so d r a s t i c a l l y a l t e r e d t h e physiography of the i s l a n d s t h a t l i t t l e of t h e o r i g i n a l h a b i t a t type remains. Breeding populat ions of t h r e e of t h e 15 seabi rd spec ie s known t o have bred on t h e i s l a n d s were e l iminated , while a few o t h e r s were a b l e t o inc rease through adap ta t ion t o man- made changes. For most b i rd spec ie s t h e a l t e r a t i o n of h a b i t a t and continued d i s tu rbance , sometimes through planned e f f o r t s t o move b i r d s t o l e s s c r i t i c a l a r e a s , sometimes through ignorant or mal ic ious perse- cu t ion , has r e s u l t e d i n seve re ly decreased roos t ing and nes t ing space and consequently i n reduced populat ions. A s p a r t of i t s study of popula t ions , breeding biology, and movements of s eab i rds of t h e c e n t r a l P a c i f i c Ocean, t h e P a c i f i c Ocean Biologica l Survey Program (he rea f t e r r e f e r r e d t o a s t h e POBSP) of t h e Smithsonian I n s t i t u t i o n , Washington, D.C., maintained one o r more b i o l o g i s t s on Sand I s l and , Johnston A t o l l almost cont inuously from 7 J u l y 1963 u n t i l 9 September 1969 (Appendix Table 1 ) . Former POBSP employees have v i s i t e d t h e a t o l l twice s ince 1969. Brian A . Harrington s tudied Sooty Terns from 18 March through 3 June 1971; A. Binion Amerson, Jr . v i s i t e d Johnston 6-12 November 1973 f o r the Of f i ce of I n t e r n a t i o n a l and Environmental Programs, Smithsonian I n s t i t u t i o n , t o update ecologica l da t a . Although primary emphasis was on t h e 12 spec ie s of breeding seabi rds , POBSP s t u d i e s a l s o included ar thropods , r e p t i l e s , mammals, and t e r r e s t r i a l p l a n t s . This r epor t i s an at tempt t o summarize t h e major r e s u l t s of t h e s e s t u d i e s and t o compile a comprehensive summary of o the r s c i e n t i f i c e f f o r t s made on Johnston A t o l l . The major t h r u s t of t h e r e p o r t i s is land-oriented r a t h e r than species-oriented, and d i scuss ions presented a r e pr imar i ly d e s c r i p t i v e r a t h e r than a n a l y t i c a l . Hopefully t h e da ta presented w i l l be u s e f u l i n developing a d e t a i l e d a n a l y s i s of t h e c e n t r a l P a c i f i c ecosystem, and f o r comparison of populat ion and breeding phenomena of t h e seab i rds and o the r groups wi th s i m i l a r d a t a from o the r i s l a n d s where t h e same spec ie s occur. This r e p o r t i s based pr imar i ly on t h e f i e l d notes and semi- monthly r e p o r t s made by t h e 29 POBSP personnel (Appendix Table 1) who maintained t h e Sand I s l and s t a t i o n . These voluminous da ta a r e s to red i n t h e National Museum of Natural His tory , Washington, D . C . This f i n a l r e p o r t i s a combination of a manuscript by Shel ton and a t echn ica l r e p o r t by Amerson (1973). Amerson's eco log ica l base l ine r e p o r t was used a s p a r t of a 10 May 1974 U.S. A i r Force Environmental Impact Statement concerning proposed d i sposa l of chemical herb ic ide on Johnston 'Ato l l . PHYSICAL ENVIRONbfENT The phys ica l c h a r a c t e r i s t i c s of Johnston A t o l l and i t s surrounding waters a r e r e l a t i v e l y we l l s tudied . The fol lowing d e s c r i p t i o n s a r e based p r imar i ly on accounts published by government agencies or by s c i e n t i s t s under government con t rac t . Johnston A t o l l l i e s between t h e l a t i t u d e s of 16?40'26" and 16"47'25" North and t h e longi tudes of 169?24'15" and 169?33'58" West (USNOO Chart 5356). I s l ands The two n a t u r a l i s l a n d s , Johnston (16'45'N x 169'32'W) and Sand (16'45'N x 169"301W), o r i g i n a l l y 46 and 10 a c r e s i n e x t e n t , l i e a m i l e and a ha l f a p a r t on t h e southern margin of t h e lagoon, which i s t h e shallow por t ion of t h e reef platform (Figs . 2 and 3 ) . Summit Peak, near t h e northwest end of Johnston I s l a n d , o r i g i n a l l y stood 48 f e e t above sea l e v e l (Chris tophersen, 1931: 3) (F igs . 4 and 5 ) . The h ighes t poin t on Sand Is land was and remains about 15 f e e t above sea l e v e l . Both i s l a n d s were formed of beachrock--sand and g rave l cemented by calcium carbonate--and loose sand, presumably wind and wave t ranspor ted ma te r i a l (Emery, 1956, and A s h o r e , 1973). From 1939 through 1942 cons t ruc t ion f o r m i l i t a r y opera t ions leve led Johnston I s l and and enlarged i t t o 211 a c r e s (Fig. 6 ) , and b u i l t another i s l e t about t h e s i z e of Sand I s l and and connected i t t o Sand Is land by a narrow causeway. These a d d i t i o n s were b u i l t mostly of c o r a l m a t e r i a l dredged from t h e lagoon i n deepening and lengthening sh ip channels and seaplane landing a reas . By 1944 Johnston Is land had a Figure 2. Map of Johnston Atoll; adapted from Wennekens (1969) and Ashore (1973). Figur e 3. Looking northeast over Johnston and Sand Islands from 3,000 feet, 12 November 1935 (U.S. Nat. Archives, R.G. 80 photograph). Figure 4. The no r theas t end of Johnston I s l and a s i t appeared from t h e south i n J u l y 1923 (B.P. Bishop Museum photo by R. S. Palmer). Figure 5. Johnston I s l and , seen from t h e no r th a t 3,500 f e e t , 1 0 October 1939 (U,S. Nat. Archives, R.G. 80 photograph). 6,100 f o o t runway, and both i s l a n d s were v i r t u a l l y covered with bu i ld ings , roadways, and gun emplacements. None of t h e o r i g i n a l sho re l ine o r vege ta t ion of Johnston Is land remained. The a i r s t r i p on Johnston was again enlarged i n 1951-52, and i n 1963-64 a d d i t i o n a l cons t ruc t ion with c o r a l dredged from t h e lagoon enlarged Johnston I s l a a d t o 570 a c r e s (Fig. 7 ) , wi th a 9,000 foo t runway, added a few a c r e s to t h e a r t i f i c i a l po r t ion of Sand I s l a n d , and b u i l t two e n t i r e l y new i s l a n d s , Alcau (North) a t 16?45'52"N x 169"31103"W and Hikina (East) a t 16?45'26"N x 169'29'19"W, of 24 and 17 a c r e s respec t - i v e l y , w i th in t h e lagoon (Bauer, 1965). The present su r faces of Johnston, Alcau, and Hikina I s l a n d s , and t h e a r t i f i c i a l po r t ion of Sand I s l and , c o n s i s t of hard packed c o r a l m a t e r i a l ranging from sand t o cobble s i z e . Bui ld ings , antennas, roads, and (on Johnston only) runways and taxiways dominate these i s l ands . Vegetat ion i s r e s t r i c t e d t o sparse lawns, s c a t t e r e d bushes and t r e e s , and t h i n l y s c a t t e r e d weedy spec ies on a r e a s t h a t a r e not f requent ly d i s tu rbed . Although bu i ld ings formerly occupied most of t h e o r i g i n a l por t ion of Sand Is land (Figs. 8 and 9 ) , t hese were removed i n t h e l a t e 1950's. A few concre te foundat ions and gun emplacements remain. The only new s t r u c t u r e s added s i n c e then a r e t h e LORAN-C t r ansmi t t e r bui ld ing and t h e 625-foot t r a n s m i t t e r tower. Ground wires r a d i a t e from t h e base of t h e tower on o r j u s t below t h e su r face , and guywires extend t o concre te p i l l a r s , most of them beyond t h e shores of t h e i s l and i n t h e lagoon (Figs. 1 0 and 11) . A roadway 3-eads t o t h e t r a n s m i t t e r bui ld ing from t h e causeway connecting t h e two por t ions of t h e i s l a n d . Except fo r t h e s e s t r u c t u r e s , t h e su r face of t h i s o r i g i n a l i s l and i s approximately l i k e t h a t of both Johnston and Sand I s l ands p r i o r t o t h e i r d is turbance . The i n t e r i o r is covered with deep, loose c o r a l sand, bound by r o o t s of t h e g ras s , Lepturus repens, and per fora ted by burrows of Wedge-tailed Shearwaters. A beachrock l aye r i s exposed around most of t h e perimeter of t h e i s l and . Geology Emery (1956) described t h e geology of Johnston I s l and based on information from 56 borings f o r bui ld ing foundat ions, ranging t o 36 f e e t below mean low water , and from s i x w e l l s d r i l l e d t o depths ranging from 86 t o 191 f e e t below mean sea l e v e l . None of these ho le s reached non-calcareous rock. Two l a y e r s of beachrock were encountered, one above sea l e v e l , and presumably co r re l a t ed wi th t h e one s t i l l exposed on Sand Is land but covered o r destroyed on Johnston, and one a t 4.3 t o 6.4 f e e t below sea l e v e l . This lower l a y e r was a l s o found 8 f e e t below sea l e v e l along bases of t h e p a r a l l e l , l i n e a r a l g a l r e e f s t h a t extend between Johnston and Sand I s l ands . These r e e f s were thought t o r e s u l t from growth of c o r a l l i n e a l g a e on t h e outcropping edges of submerged beachrock. Below t h e beachrock t h e deeper p a r t s of t h e we l l s showed a l t e r - na t ing sand, loose c o r a l , and sand and c o r a l , wi th l i t t l e c e r t a i n t y of Figure 6. Looking north over Johnston Island, 9 April 1942 (U.S. Nat. Archives, R.G. 80 photograph). 16"45' N -1G044' 0 . 5 i i au t ica l Miles 16"43' 16g033' 169:32' 169P31' Figure 7. Profile map of Johnstbn Island, Johnston Atoll, 1923, 1942, and 1964; adapted from Ashore (1973) and USNOO Chart No. 5356, 20 May 1963 and 23 December 1967. Figu Ire 8. Sand I s l and from t h e no r th , probably i n 1939 (U.S. Nat. Archives, R.G. 80 photograph). Pigu r e 9. Sand Is land from t h e s m t h e a s t , 18 March 1940; bui ld ings l a t e r covered t h e e n t i r e i s l a n d , inc luding t h e nor theas t peninsula (U.S. Nat, Archives, R.G. 80 photograph). Figure 10. Sand I s l and a s i.t appeared from t h e southeas t about 1962, with the U, S. Coast Guard I , O l a l S t a t i o n completed ( o f f i c i a l U, S. Coast Guard photograph). F igure 11. Sand I s l and a s i t appeared from t h e wes t , c i r c a 1965, a f t e r 1964 cons t ruc t ion had added a few a c r e s t o t h e south s i d e of t h e man-made por t ion of t h e i s l a n d ( o f f i c i a l U.S. Coast Guard photograph). c o r r e l a t i o n from wel l t o wel l . Mud of unknown o r i g i n occurred i n s e v e r a l we l l s . s e v e r a l occurrences of non-calcareous rock a r e known from t h e i s l a n d s . Several hundred pounds of pumice f l o a t e d ashore i n 1953, presumably from volcanic a c t i v i t y on San Benedicto I s land of f Mexico (Emery, 1956: 1516, and Richards, 1958). Maxwell S. Doty found a small p i ece of r h y o l i t e imbedded i n beachrock on Sand I s l and . 'This could have been r a f t e d on driftwood or could have a r r i v e d mas s h i p ' $ b a l l a s t (Emery, 1956: 1516). Pumice a l s o f l o a t e d ashore i n t h e 1960's . Although Johnston A t o l l l i e s s eve ra l hundred mi l e s from t h e n e a r e s t i s l a n d , it i s f a i r l y c l o s e l y a s soc ia t ed wi th two submerged mountain ranges. The n e a r e s t i s t h e Mid-Pacific Mountains, a l s o ca l l ed t h e Marcus-Necker Rise , which l i e i n an a r c extending from near t h e middle of t h e Hawaiian Ridge (Necker I s land) f i r s t southwester ly, then wes te r ly t o Wake I s l and , then northwester ly t o Marcus I s l and . Barkley (1962: 3) considered Johnston t o be a p a r t of t h i s range, but Kroenke and Woollard (1965: 365) and Ashmore (1973: 3) considered i t t o be t h e no r theas t e rn extremity of Christmas Ridge (formerly t h e Line Is land Ridge). Johnston l i e s about 100 nm southeas t of t h e c r e s t of t h e Mid- P a c i f i c Mountains and i s separa ted from i t by water over 5 km deep. It i s more d i r e c t l y al igned wi th t h e long a x i s of the Line I s l ands , but i t is separa ted from t h e nea res t of t hese (Kingman Reef) by a d i s t a n c e of about 740 nm and by depths of over 5 h~, al though submerged mountains rise t o much shallower depths i n seve ra l p l aces between t h e two (Menard, 1964: F igs . 1 .7 , p. 14 and 1.12, p. 19 ) . Both ranges were b u i l t up from t h e ocean f l o o r by repeated volcanic f lows. Subsequent i s o s t a t i c readjustment and eros ion a t and above sea l e v e l then lowered t h e mountains. Corals and c o r a l l i n e a lgae grew i n shal low waters around these peaks, and under favorable condi t ions maintained i s l a n d s by growing upward a s r a p i d l y a s t h e underlying range sank. But not a l l peaks subsided a t a t ime when c o r a l growth was favored, or they sank too r a p i d l y f o r c o r a l s t o main ta in t h e su r face . P a r t i c u l a r l y i n t h e Mid-Pacific Mountains, a l a r g e number of f l a t topped "guyots," presumably drowned i s l a n d s wi th t h e i r t ops 1 t o 2 km below the su r face , were discovered during World War I1 (Hess, 1946). Menard (1964: 92) discussed t h e r e l a t i v e ages of t h e c e n t r a l P a c i f i c mountain groups. I n summary, many of t h e volcanoes forming t h e Mid-Pacific Mountains were thought t o be h igh i s l a n d s by middle Cretaceous time (roughly LOO m i l l i o n yea r s ago) on t h e b a s i s of f o s s i l s dredged from t h e summits of IIess, Cape Johnson and o t h e r guyots a few hundred mi l e s west of Johnston (Hamilton, 1956, and Matthews, et al., 1974). Although vulcanism and i s l a n d formation con- t inued f o r some time i n t h e r eg ion , t h e i s l a n d s were eroded and t h e r eg ion g radua l ly submerged. Some of t h e i s l a n d s probably s t i l l ex is ted i n t o l a t e Mesozoic-early Cenozoic time, but except f o r Wake none has survived t o t h e present i n t h e c e n t r a l P a c i f i c . The Line I s l ands probably were formed i n l a t e Mesozoic o r e a r l y Cenozoic time, 60 t o 70 m i l l i o n yea r s ago. D e t a i l s of t h e geologica l h i s t o r y of Johnston A t o l l i t s e l f a r e lacking . When i t f i r s t appeared a s an i s l a n d , i ts o r i g i n a l s i z e , r a t e of e ros ion and subsidence, and r a t e of c o r a l growth a r e unknown. No deep d r i l l i n g or seismic s t u d i e s which would r evea l t h e depth of t h e c o r a l cap have been repor ted . Gravi ty measurements by Kroenke and Woollard (1965) show Johnston A t o l l t o be in termedia te between t h e main Hawaiian I s l ands and t h e Line I s l a n d s i n Bouguer anomaly va lues , which may i n d i c a t e t h a t t h e base of heavy volcanic m a t e r i a l i s more massive under Johnston than under t h e Lines but l e s s massive than under t h e Hawaiian I s l ands , where heavy b a s a l t s stand f a r above sea l e v e l i n t h e southeast and l i e a t most a few hundred f e e t below sea l e v e l a t Midway a t t h e northwest end of t h e chain (Ladd, Tracy, and Gross, 1967). Bouguer anomaly g rad ien t s on Johnston were lower by about ha l f than i n t h e Hawaiian Chain, which may mean t h a t t h e r e a r e no vo lcan ic neclcs or plugs involved i n t h e upper s t r u c t u r e of Johnston i n c o n t r a s t t o t h e Hawaiian I s l a n d s , including t h e northwest cha in . Geomorphology The a t o l l c o n s i s t s of a c o r a l platform wi th over 50 square mi l e s of a rea under l e s s than 100 f e e t of water . A marginal r e e f , exposed only a t lowest t i d e s , extends f o r 9 m i l e s along t h e northwest margin of t h e platform. A broad shallow r i d g e , on which l i e Johnston, Sand, and Hikina I s l a n d s , extends from t h e west end of t h e marginal reef eastward, then northward t o enc lose a lagoon approximately 7 by 2 mi l e s i n ex ten t , with depths gene ra l ly between 1.0 and 30 f e e t . The remainder of t h e platform l i e s south and e a s t of t h e lagoon and i s mostly deeper ( see F ig . 2 ) . Emery (1956) s tudied t h e composition of t h e reef platform by making v i s u a l es t imates of t h e r e l a t i v e percentages of sand, c o r a l , and c o r a l l i n e a lgae on photographs of about 4 percent of t h e platform, i n which t h e bottom mate r i a l could be i d e n t i f i e d by color t o a depth of about 10 fathoms. Surfaces of c o r a l l i n e a lgae dominated along t h e main outer r e e f , and many patch r e e f s l e s s than 4 fathoms deep through- out t h e lagoon were topped wi th c o r a l l i n e a lgae (Fig. 12) . The deep e a s t e r n p a r t of t h e platform showed no evidence of a l g a l patch r e e f s . Coral-dominated a r e a s occurred throughout t h e lagoon and platform, and c o r a l made up t h e s u b s t r a t e of many algae-topped patch r e e f s . Between patches of c o r a l and c o r a l l i n e a l g a e were s t r i p s of sand, including dune-like s t r u c t u r e s near Johnston and Sand I s l ands . Sand dominated t h e e a s t e r n half of t h e platform. The Johnston A t o l l platform d i f f e r s from t y p i c a l a t o l l s i n t h a t t h e main outer reef extends only about one-fourth of t h e way around the perimeter . I n add i t ion , n e i t h e r t h e well-defined northwestern marginal reef nor t h e poorly developed southern reef i s i n a c l e a r l y defined windward or leeward pos i t i on ; most a t o l l s d i sp lay b e t t e r developed r e e f s on t h e windward s i d e . Emery (1956) thought t h a t e i t h e r t h e windward por t ion of t h e reef had been removed by eros ion during a time of lowered sea l e v e l s c . t h a t the platform had t i l t e d southeastward. He s l i g h t l y favored the t -1 t ing hypothesis. E.H. Bryan, Jr . (ms.) noted t h a t t h e c o r a l beds on Sand Is land dipped 4 t o 5 degrees southeastward, which would i n d i c a t e pos- s i b l e t i l t i n g i n t h a t d i r e c t i o n . Ashmore (1973) s tudied t h e morphology of t h e a t o l l on the b a s i s of d a t a c o l l e c t e d mainly by a team of U.S. Naval Oceanographic Off ice engineers and Naval personnel from t h e USS W R Y during 1964. These da ta showed f e a t u r e s t h a t were not evident t o Emery, and led Ashmore t o favor a sea l e v e l c h a n g e t o expla in t h e p resen t morphology of t h e a t o l l , a l though he aclcnowledged t h e p o s s i b i l i t y of a combination of sea l e v e l change and t i l t i n g . The major f e a t u r e Ashmore found t h a t d i d not f i t t h e t i l t i n g hypothesis was t h a t t h e platform was composed of two more or l e s s d i s t i n c t l e v e l s , n e i t h e r wi th measurable s lope (Fig. 13 ) . These were separated by an uneven scarp , 500 t o 1,000 yards wide, with an average gradient of 1 t o 2 percent , extending ac ross t h e e n t i r e platform. The higher l e v e l i s approximately 25 t o 30 f e e t below mean low water and, inc luding t h e lagoon, covers about 24 square mi les . It i s i r r e g u l a r i n o u t l i n e wi th s i g n i f i c a n t embayments south of Johnston I s l and , a t t h e e a s t e r n t i p of t h e platform, and a t a break i n t h e northernmost s e c t i o n of t h e outer r e e f . The most s t r i k i n g f e a t u r e of t h i s l e v e l i s t h e g r e a t number of sink-lilce ho le s , commonly 55 t o 60 f e e t deep, and some exceeding 112 mi le i n l eng th . The lower l e v e l has depths of 55 t o 65 f e e t below mean low water and extends over an a rea of about 30 square mi l e s . A depression a t l e a s t 90 f e e t deep and about 5 square mi l e s i n a rea l i e s i n t h e extreme eas t e rn po r t ion of t h i s l e v e l . Otherwise t h e lower l e v e l i s somewhat dished, wi th a d i s t i n c t r i m extending t o wi th in 33 f e e t of mean low water , along much of t h e southern and western edge. I n c o n t r a s t t o t h e upper l e v e l , t h e lower l e v e l has few kno l l s , no s inkholes , and no patch r e e f s . Ashmore suggested t h a t these t e r r a c e s were formed a s sea l e v e l s f e l l a t t h e end of t h e Sangamon I n t e r g l a c i a l , about 75,000 years ago, or with r i s i n g sea l e v e l s a t t h e end of t h e Wisconsin g l a c i a t i o n , 10 t o 12 thousand yea r s ago. The s inkholes i n t h e upper l e v e l were thought t o have been formed by f r e s h water e ros ion and hence were in t e rp re t ed a s s t rong evidence t h a t t h i s l e v e l was o lde r than t h e lower, which would i n d i c a t e formation of t h e t e r r a c e s during s t a b l e per iods wi th in a genera l period of f a l l i n g sea l e v e l s . But t h e upper l e v e l appeared t o Ashmore t o be too wel l preserved t o have withstood 65,000 years of s u b a e r i a l e ros ion during low waters of t h e Wisconsin g l a c i a l per iod , which would i n d i c a t e more r ecen t formation, during r i s i n g sea l e v e l s . Present d a t a a r e i n s u f f i c i e n t t o r e so lve t h e problem. Figure 12. Johnston A t o l l r ee f p r o f i l e s ; A:OUter r e e f , B: i s o l a t e d patch r e e f . Adapted from Emery (1956) and WenneIcens (1969). A-Presenl so3 level B-Assr!~?;! to predate 6Z becauso of the depth d the noiul i~n holes D - A s ~ t l n l n d 10 Predate boll> B8.C due la the absencs ol sa!i;tion hole: deeper than C . - -. -- -. - -- . -- il Figure 13 , 3equence of s ea l e v e l changes, Johnston A t o l l (Ashore , 1973). Cl imate Weather r e c o r d s a r e avai . l .able f o r t h e a t o i l . from abou t 1931. t o iiie p r e s e n t , h u t s t a n d a r d i z e d d a t a have been recorded on1.y s i n c e 1952 (.ic.:.iiir 'Ta.slc Force Seven, 9 and U.S. Dept . of Co~nmerce, 1 9 7 2 ) . i !,i-:::! r e c o r d s show a tropic.aS. inar ine c l i m a t e wizh l i t t l e v a r i a t i o n .. ; , i . . :~~ lpe ra tu re and wind speed , b u t g r e a t variabi.:l.%.ty i.n ra.inia.l.1. i.s no ev idence tila:. c l i m a t i c c o n d i t i o n s d i . f f e r Ero~ri one e a t o U t o a i lo the r . The i s l a n d s a r e too low and sn1al.l t o own weather s i g n j f i c a n t l y . The on ly observed i n f l u e n c e ..,. . d s on t l i e i r own weather was t h e devel~opment of wel.1- o~.-g~~.~,i.::etl i:hermai updraf t -s g e n e r a t e d by s o l a r h e a t i n g of a i r next: t o t l~ic iu?f:nccs of Joi~llstori and Sand I s l a n d s on t h e r a r e clays rullen winds were ic:;s tiran 8 t o 1 0 lcnots. At tent i .on was draw^? t o t h i s u p d r a f t from S:ii?d I s l a n d by t h e coluin;~ of s o a r i n g Great: P r i ~ g a t e b i r d s and Sooty Ter11.s t h a t devel.oped wi i l l i i l i.t. Li~.dividuaS. b i r d s e n t e r e d t h % s col.umi. n e a r t h e west s h o r e o f t l ic i.i;l.and and r o s e t o nea r t h e c loud b a s e s a t over 1 , 0 0 0 f e e t a:Lt:i..tude i n 1.5 t o 30 minu tes . Dur ing t h i s r:i.me t h e y dr:i.Fted n i:i~:i.rd t o h a l f a m i l e downwind Eroin the. i s l a n d , Above t h e b i r d s t h e r e appeared t o be a cumulus bui~l.dup a t t h e top oil t h e co l~un~n o:F a i r . Tl?ere appeared t:o be a s i m i l a r h u t Larger cumuius buil.dup downwind rr-om Johns ton i s l ~ a ~ ~ d a t t h e same t ime, b u t fewer b i r d s used t11:i.s u p d r a f t , probah1.y because fit was f a r t h e r From t h e bi.rd c o l o n y on Sand Zs:Land. There Tias no :iindi.cation t h a t p r e c i p i t a t i o n was g e n e r a t e d from t h i s phenomenon. I n terms of winds , t e m p e r a t u r e , and p r e c i p i t a t i o n , two broad s e a s o n s c a n be d : i s t i . n g ~ ~ i s h e d on. t h e atoll^. Tiie 4-month "win te r" i n c l u d i n g t h e months December th rough March i s cha l rac te r i zed by s l i g h t l y lower t e m p e r a t u r e s , more v a r i a b l e winds, and h e a v i e r pre- c i p i t a t i o n . t h a n t h e 8-month "summer" extci ldi i ig from Apri.1. th rough November. Temperature The mean annua l t e m p e r a t u r e i s 79.3'F (26.3"C). D a i l y r a n g e s a r e u s u a l l y o n l y 7 o r 8 d e g r e e s ( F ) , and t l ie da: i ly inax:i.n~um and minimum t e m p e r a t u r e s v a r y o n l y a few d e g r e e s th roughout t h e y e a r ( F i g . 1 4 ) . The ext remes range from a l.ow of 62'77 (16.5'C) Olece~nber 1964) t o a h i g h of 89?F (31.5"C) (October 1968, J u l y and November 1969) , which i s lower t h a n t h e d a i l y r a n g e f r e q u e n t l y encoun te red i n c o n t i n e n t a l a r e a s . The cons tancy of t e m p e r a t u r e r e s u l t s from t h e a i r masses p a s s i n g over t h e a t o l l having been modi f i ed by c l o s e c o n t a c t rvith t h e ocean f o r thousands of miles. Thus t h e a i r t e m p e r a t u r e i s n e a r t h a t of t h e w a t e r . Sea s u r f a c e t e m p e r a t u r e s ( F i g . 14) v a r y i . i . t t l e from day t o day and change o n l y s lowly w i t h t h e s e a s o n s . Winds - J o h n s t o n l ies w i t h i n t h e b e l t of s t r o n g e a s t e y l y t r a d e winds through- o u t most of t h e y e a r , b u t t h e s e r e a c h a maximum i n r! ?; .rh, s p e e d , and L- 60?F 7--,---7-7- 1 F M A M J J A S O N D F i g u r e 1 4 . Mean monthly a i r and s e a t e m p e r a t u r e s , Johns ton A t o l l , 1931-1972; a i r : ( s o l i d l i n e ) , dai1.y maximum and minimum ( d a s h e s ) , ext remes ( d o t s ) ; s e a : means ( b a r r e d ) . Adapted from S e c k e l (1962) and U.S . Department of Commerce (1972). s t e a d i n e s s d u r i n g t h e summer. Only d u r i n g t h e w i n t e r p e r i o d , when t h e world wind b e l t s s h i f t southward t o t h e i r maximum e x t e n t , do t r a d e winds (NE th rough ESE) occur l.ess than 80 p e r c e n t of t h e t ime (F ig . 1 5 ) . Dur ing t h i s p e r i o d l i g h t v a r i a b l e winds and w e s t e r l i e s occur o c c a s i o n a l l y a s s o c i a t e d w i t h t h e passage of o rgan ized d i s t u r b a n c e s - - e a s t e r l y waves, t r o u g h s a l o f t , and weak c o l d f r o n t s - - c h a r a c t e r i s t i c of more t empera te r e g i o n s . Mean a n n u a l s u r f a c e wind speed i s 1 5 . 1 m i l e s p e r hour , and t h e monthly means r a n g e o n l y from 113.6 t o 1 6 . 0 ( F i g . 1 6 ) . Monthly ex t remes , e x c l u d i n g 1972, r a n g e from 35 mph i n J u l y t o 49 mph i n March and November. Mean monthly ext remes a r e 43 mph. U n t i l 1972 t h e r e was no " J F M A M j J A S O N D F i g u r e 15. P e r c e n t f r e q u e n c y of wind from E and ENE (open b a r ) and ESE and NE ( s t i p p l e d b a r ) , J o h n s t o n A t o l l . - F i g u r e 16. Mean month ly wind s p e e d , J o h n s t o n A t o l l , 1931-1972; means ( s o l i d l i n e ) , u p p e r ex t r emes ( d o t s ) . Adapted from U.S. Depar tment o f Commerce (1972). record of a storm of hurr icane f o r c e (winds of 64 knots or more) having passed over Johnston. On 1 9 August 1972 hurr icane Ce les t e , spawned off t h e southern coas t of Mexico some 3,000 nm t o t h e e a s t nea r ly 2 weeks e a r l i e r , passed 25 mi l e s no r theas t of Johnston. The wind speed on t h e i s l and h i t an a l l time high of 104 mph, and d id minor damage on t h e a t o l l . Observations from weather s a t e l l i t e s i n d i c a t e t h a t t r o p i c a l storms i n t h e Johnston A t o l l a r e a , though in f r equen t , may not be a s unusual a s was once supposed. A l o f t winds a r e described by Figures 17 and 18 i n which e a s t - west o r "U" components and north-south o r "V" components of wind d i r e c t i o n and v e l o c i t y a r e p lo t t ed a g a i n s t a l t i t u d e i n f e e t and barometric pressure i n m i l l i b a r s . Since t h e a i r flow i s predominantly east-west a t a l l a l t i t u d e s , t h e "U" components show by f a r t h e h ighes t v e l o c i t i e s . The comparatively shallow t r a d e winds a r e shown below t h e lowest 0 i s o p l e t h of Figure 17. Above t h e t r a d e s , a i r cu r ren t s i n t h e upper trophosphere (20,000 t o 60,000 f e e t ) a r e predominantly wes ter ly throughout t h e yea r , with a maximum of speed, depth , and s t e a d i n e s s i n March and Apr i l . These winds have a considerable north-south component i n December and January, wi th an e spec ia l ly s t rong n o r t h e r l y component i n February (Fig. 18 ) . Above t h e trophosphere (above t h e h ighes t 0 i s o p l e t h on Figure 1 7 ) , s t r a t o s p h e r i c flow i s dominated by the Krakatoa e a s t e r l i e s , bu t t h e r e i s cons iderable seasonal v a r i a b i l i t y . Winter i s charac ter ized by r e l a t i v e l y l i g h t winds gene ra l ly wi th e a s t predominating i n t h e lower s t r a t o s p h e r e (60,000 t o 90,000 f e e t ) , west dominating t h e mid- l e v e l s (90,000 t o 110,000 f e e t ) , and e a s t e r l i e s again above 110,000 f e e t . A f a i r l y rap id t r a n s i t i o n occurs during spr ing t o s t rong , s teady e a s t e r l i e s , reaching a maximum i n Ju ly and August. There i s a sharp t r a n s i t i o n back t o l i g h t v a r i a b l e winds i n t h e f a l l . P r e c i p i t a t i o n Mean annual p r e c i p i t a t i o n i s 26.11 inches , but year-to-year v a r i a t i o n i s g r e a t (Fig. 19) . For example, t h e t o t a l f o r 1968 was 42.27 inches, making i t t h e we t t e s t year on record , while 1969 had only 17.11 inches , next t o t h e lowest yea r ly t o t a l recorded. Lowest was 12.86 inches i n 1953. This v a r i a t i o n i s r e f l e c t e d s t rong ly i n growth of vege ta t ion on t h e i s l a n d s . Twice during POBSP s t u d i e s , i n spr ing 1966 and i n l a t e 1969 and again i n November 1973, extended d ry per iods r e su l t ed i n t h e o r i g i n a l po r t ion of Sand Is land becoming a v i r t u a l d e s e r t . March, Apr i l , and May 1966 were d r i e s t on record fo r these months, and May 1966, wi th only 0.11 inch was the d r i e s t month ever recorded. Atmospheric d is turbances t h a t occur during t h e four winter months br ing i n coo le r , l e s s humid, l e s s s t a b l e a i r , which r e s u l t s i n more cumulus build-up and heav ie r , more frequent p r e c i p i t a t i o n than occurs during t h e 8-month summer season, when l i g h t showers r e s u l t i n g Figure 17. Johnston A t o l l mean U components; adapted from J o i n t Task Force Seven (~1959). 110,000- hiLiLoc!e i:: i e r l BaromPfric "'rsr,,rr in J A i 9 F E B :IAR APR !MAY JUN JUL fiUG SEP OCT NOV DEC " . i ? l i h r r s Figure 18. Johnston A t o l l mean V components; adapted from J o i n t Task Force Seven (1959). Figure 19. Mean monthly p r e c i p i t a t i o n , Johnston A t o l l , 1931-1972; means ( s o l i d l i n e ) , extremes (do t s ) . Adapted from U.S. Department of Commerce (1972). 65 1 I J F M A M J J A S O N D F i g u r e 20. Mean monthly r e l a t i v e humidi ty , Johnston A t o l l , 1931-1972; a l O O hours (do t s ) , 0700 hours (da shes ) , 1300 hours ( s o l i d l i n e ) , 1900 hours (bar red) . Adapted from U.S. Department of Comerce (1972). from small build-ups of cumulus clouds generated by t h e shallow t r a d e winds a r e t h e usua l source of p r e c i p i t a t i o n . The four winter months average 2.75 inches of r a i n f a l l and t h e e i g h t summer months 1.87 inches. However, i n Apr i l and again i n September-November heavy showers asso- c i a t e d with t h e passage of t r o p i c a l storms o r depressions a r e not uncommon. The mean r e l a t i v e humidity i s 75 percent , being h ighes t a t 0100 hours (78 percent ) and lowest a t 1300 hours (69 percent ) . Monthly mean va lues vary l i t t l e throughout t h e yea r , but a r e d e f i n i t e l y lower i n January and February and i n June and J u l y than during t h e r e s t of t h e year (Fig. 20). Sky Cover Mean monthly sky cover, sun r i se t o sunse t only, i s 6.0 on a s c a l e of 0 f o r no clouds t o 10 f o r complete sky cover (Pig. 21) , wi th l i t t l e v a r i a t i o n throughout t h e year . During a n average year t h e r e a r e 75 c l e a r days, 172 p a r t l y cloudy days, and 118 cloudy days (Fig. 22) Figure 21. Mean monthly sky cover, s u n r i s e t o sunse t , Johnston A t o l l , 1931-1972. Sky cover i s expressed i n a range of 0 t o 3 a s being c l e a r , 4 t o 7 a s p a r t l y cloudy, and 8 t o 10 a s cloudy. Adapted from U.S. Department of Commerce (1972). 3 . 2 - 1 - 0 J F M A M J J A S O N D Figure 22, Mean monthly number of days of c l e a r s k i e s ( so l id l i n e ) , p a r t l y cloudy s k i e s (do t s ) , cloudy s k i e s (barred) , and p r e c i p i t a t i o n of 0.01 inch o r more (dashes), Johnston Ato l l , 1931-1972. Adapted from U,S. Department of Commerce (1972) . Oceanography C h a r a c t e r i s t i c s of t h e waters surrounding Johnston A t o l l a r e described on t h e b a s i s of s t u d i e s made by the Bureau of Commercial F i s h e r i e s , U.S. F i sh and Wi ld l i f e Serv ice (Seckel, 1962 and 1968, and Barkley, 1972) and more d e t a i l e d s t u d i e s of the immediate v i c i n i t y of t h e a t o l l and wi th in t h e a t o l l a r e based on s t u d i e s by the Off ice of Naval Research (Kopenski and Wennekens, 1966, and Wennekens, 1969). Major Water Masses and Currents The major su r face water mass of t h e Hawaiian and Johnston region i s c a l l e d North P a c i f i c Cent ra l (Fig. 23). These waters have a s a l i n i t y genera l ly g rea t e r than 34.8 0100 and range up t o 35.3 0100 (Seckel, 1962 and 1968). They flow i n a huge clockwise gyre, t h e southern limb of which moves p a s t t h e Hawaiian I s l ands and Johnston A t o l l a s the North Equator ia l Current , a b e l t of water s eve ra l hundred mi l e s wide and seve ra l hundred f e e t deep moving a t up to 112 knot. South and e a s t of t h i s water mass i s t h e Ca l i fo rn ia Current Extension, cons i s t ing of waters t r a n s i t i o n a l between North P a c i f i c Cent ra l and North P a c i f i c Equator ia l , a smaller mass of lower s a l i n i t y , u sua l ly l e s s than 34.2 0100. The C a l i f o r n i a Current Extension s t r e t c h e s wes ter ly during t h e summer t o r e c i r c u l a t e i n t o t h e Equator ia l Counter- c u r r e n t west of 175' longi tude , but weakens i n t h e f a l l t o r e c i r c u l a t e between 160" and 170?W (Seckel, 1962: 407). Seckel pointed out t h a t t h e spr ing and summer invasion of t h e Hawaiian I s l ands reg ion by t h e Cal- i f o r n i a Current Extension c o r r e l a t e s wi th t h e a v a i l a b i l i t y of sk ip j ack (Katsuwonus pelamis) . He thought t h e c o r r e l a t i o n cou1.d be a d i r e c t r e s u l t of t h e invasion of t h e lower s a l i n i t y waters or could r e s u l t from a dynamic e f f e c t produced when t h i s cu r ren t entered t h e reg ion . This season a l s o c o r r e l a t e s f a i r l y w e l l wi th t h e breeding seasons of most Hawaiian and Johnston A t o l l s eab i rds . The Equator ia l Countercurrent does not reach t h e immediate v i c i n i t y of Johnston A t o l l , but ma.y be near enough t o make a s i g n i f i - cant con t r ibu t ion to t h e a t o l l ' s b i o t a . It i s a shallow e a s t e r l y flowing c u r r e n t , wi th s a l i n i t y l e s s than 34.5 o/oo, which flows a t up t o 2 knots roughly between SON and 1 O 0 N l a t i t u d e (Svedrup, Johnson, and Fleming, 1942). During spr ing and summer, when i t i s f a r t h e s t no r th , i t may reach to within 300 nm of Johnston A t o l l and thus probably i s within feeding range of Johnston seabi rds (Gould, 1974a). This cu r ren t s p i r a l s clockwise t o an observer fac ing e a s t , with the l a t e r a l (north-south) component about a f i f t h the v e l o c i t y of t h e west t o e a s t v e l o c i t y . Thus t h e r e i s upwelling and divergence along t h e boundary between t h e countercurrent and t h e wes ter ly flow- ing waters of t h e North Equator ia l Current . Svedrup, e t a2. (1942: 712), Ashmole and Ashmole (1967), and Gould (1974a) present evidence t h a t t h i s boundary and waters flowing away from i t a r e highly product ive of marine organisms. Figure 23. P a c i f i c Ocean cu r ren t s (King, 1967) . Local Waters and Currents Waters near t h e a t o l l were described by Wennekens (1969) a s having temperatures ranging between 25 and 27?C and s a l i n i t i e s between 34.6 and 34.8 o/oo i n t h e upper 100 meters . S a l i n i t y increased with depth t o a maximum s l i g h t l y i n excess of 35 o/oo between 100 and 200 meters , then decreased t o a minimum of s l i g h t l y over 34.3 o/oo a t about 400 meters , then decreased slowly t o about 34.6 0100 a t 2,000 meters. The main thermocline was found between about 100 and 400 meters , with temperatures decreasing from about 25 t o about 7'C. Below 400 meters temperature decreased slowly t o about 2?C a t 2,000 meters . The region of s t eep g rad ien t s i n both temperature and s a l i n i t y between 100 and 400 meters was highly s t a b l e because of rap id change i n dens i ty co r re l a t ed wi th these changes i n phys ica l c h a r a c t e r i s t i c s . Intermixing of waters above and below t h i s reg ion was i n h i b i t e d . Although T i m e (1963) repor ted zooplankton l e v e l s i n t h e waters moving pas t Johnston t o be very low, and Ashmore (1973) reported t h a t f i s h e s were seldom seen beyond t h e immediate a t o l l a r e a , t h e l a r g e submerged bases of a t o l l s such a s Johnston d e f l e c t t h e waters and cause leeward eddies with l o c a l a r e a s of n u t r i e n t turnover and enrichment ( S e t t e , 1955). King (1967) and Gould (1974a) show t h a t a r e a s wi th in 100 mi l e s of t h e s e i s l and upwellings provide most of t h e food resources f o r l a r g e seabi rd co lonies . Wennekens (1969) described t h e i n t e r a c t i o n s of t h e North Equator ia l Current and l o c a l t i d e s with t h e a t o l l , based on extens ive s t u d i e s with dye markers and parachute drogues designed t o measure flow a t depths down t o 3,000 f e e t . The purpose of h i s s tudy was t o ob ta in information u s e f u l f o r minimizing e f f e c t s of p o l l u t i o n of a t o l l waters . H i s information indica ted t h a t deeper waters flowed r a t h e r smoothly around t h e a t o l l , but t h a t a d i s t i n c t " i s land wake" formed i n the su r face l a y e r s . He recognized t h r e e seasonal flow regimes o r p a t t e r n s around and over t h e a t o l l (Fig. 24). One regime extended from l a t e November t o e a r l y March and was charac ter ized by a s t rong o f f shore cu r ren t s e t t i n g gene ra l ly south- west, with i s l and wake confined mainly t o t h e southwestern quadrant and a prominent convergence forming along t h e seaward margin of t h e i s l and platform during r i s i n g t i d e . Barkley (1972) suggests t h a t i n February ~ o h n s t o n ' s wake extends some 600 km downstream. The second regime l a s t e d from e a r l y March through mid-June and was charac ter ized by a s t rong o f f shore cu r ren t s e t t i n g genera l ly northwest with i s l and wake confined mainly t o t h e northwest quadrant. An a c t i v e e a s t e r l y counterf low developed along t h e seaward edge of t h e reef during per iods of f a l l i n g t i d e . The t h i r d regime extended from mid-June t o e a r l y December and was charac ter ized by moderate of fshore cu r ren t s e t t i n g genera l ly westward. Is land wake was confined mostly t o t h e western and north- western quadrants. - . sironr3 3..:;~!-~;:,: Current . , , c,.;clil,jj.s VJ-S Johnston Is land C t i r r e n t Regimes Flow deflects D a i l y TidcI Flow Regime Figure 24. Seasonal and t i d a l flow regimes, Johnston Atoll. (Wennekens, 1969) The e f f e c t s of l o c a l t i d e s were t o d e f l e c t c u r r e n t s t o t h e l e f t during r i s i n g t i d e and t o t h e r i g h t dur ing f a l l i n g t i d e s . During t h e June t o December per iod , when o f f shore c u r r e n t s were only moderate, l o c a l t i d e s induced a r o t a r y or semi-rotary motion t o t h e c u r r e n t s , r eve r s ing t h e wes ter ly f low during f a l l i n g t i d e s . The flow wi th in t h e lagoon was complicated by t h e e f f e c t s of t i d e and t h e presence of i s l a n d s and channels . Some of t h e p a t t e r n s i n f e r r e d from e a r l i e r work (Kopenski and Wennnekens, 1966) a r e shown i n F igures 25 through 27. Wennekens' (1969) pub l i ca t ion conta ins numerous diagrams and a e r i a l photographs showing these flow p a t t e r n s i n g r e a t d e t a i l . Kopenski and Wennekens (1966) thought t h e d i s tu rb ing inf luence of man on t h e marine environment of Johnston A t o l l t o be minimal, except f o r l o c a l i z e d des t ruc t ion of l i v i n g c o r a l and t h e r e l e a s e of f i n e sediments. They suggested t h a t t h e enlargement of Johnston and Sand I s l ands and t h e c r e a t i o n of t h e two small i s l a n d s a f f ec t ed t h e genera l c i r c u l a t i o n only i n a minor way. A t t h e l o c a l l e v e l , however, they found t h a t c i r c u l a t i o n had been g r e a t l y a f f e c t e d . The dredging of boat channels , tu rn ing bas ins , e t c . , e s p e c i a l l y between Akau I s l a n d , Sand I s l and , and t h e southern t i p of t h e main reef had crea ted new and a r t i f i c i a l flow channels. The geometry of t h e shore l ine of t h e man- made i s l a n d s a l s o cont r ibuted t o t h e c r e a t i o n of vor texes , s t agna t ion po in t s , and ven tu r i c e f f e c t s , which s h i f t i n loca t ion and vary i n DURING W E S T E R L Y F L O W , T U R B I D WATER I S T R A N S P O R T E D T O T H E W E S T AND S O U T H W E S T A S I N D I C A T E D AND S E T S W E S T W A R O Figure 26. Johnston Atoll inferred lagoon circulation and turbid outflbw (westerly flow), July-August 1965 (Kopenski and Wennekens, 1966) DLRII:G EASTERLY FLOW, T U R B I D T U R B I D "CLOUD" ~ n i ER BECOMES " S Q U E E Z E D " '7'BROKEN O F F . At.O!'~ _-.__.,__...__- ,.. _ . .: T U n e l D "CLOUD" \.-'- 9 G i A K I N G OFF 169'10' Figure 27. Johnston Atoll inferred lagoon circulation and turbid outflow (easterly flow), July-August 1965 (Kopenski and Wennekens, 1966) i n t e n s i t y a s t h e r eg iona l c i r c u l a t i o n changes. I n add i t ion , t h e wes ter ly extension of Johnston Is land created a backwash immediately south of t h e i s l and during t h e summer, r e s u l t i n g i n very l imi t ed mixing of waters i n t h a t a r e a . Tides Wennekens (1969) described t h e l o c a l t i d e s a s "...mixed type, predominantly semi-diurnal, u sua l ly wi th two d a i l y high and low waters exh ib i t ing s t rong i n e q u a l i t i e s i n t h e ampli tudes of t h e high waters . The i n e q u a l i t i e s i n t h e high reach a maximum a t t h e time of maximum moon d e c l i n a t i o n . . . . I ' H i s t i d e graphs show t h e h ighes t high t i d e s t o have amplitudes of a l i t t l e under 3 f e e t and t h e lowest high t i d e s with amplitudes of under 2 f e e t . Seismic or Tsunami Waves The c h a r a c t e r i s t i c s of seismic o r Tsunami waves--long g r a v i t y waves caused by submarine earthquakes, l ands l ides , or p lu ton ic ac t iv i ty - - a t Johnston A t o l l were described by'wennekens (1969). From a v a i l a b l e h i s t o r i c a l d a t a (Fig. 28), he found t h e l a r g e s t amplitude wave recorded t o he about 3.4 f e e t , r e s u l t i n g from t h e Chilean earthquake of 22 May 1960. The c r e s t of t h e wave a t Johnston Is land appeared a s a pro- g r e s s i v e r i s e i n sea l e v e l , wi th maximum e leva t ion being reached i n 25 t o 30 minutes. The period of seismic waves a t t h e i s l a n d appeared t o be between 45 and 60 minutes. Wennekens (1969: 6-7) f u r t h e r suggested t h a t h i s t o r i c a l records " . . . ind ica te t h e e f f e c t s of a Tsunami a t Johnston I s l and should be minimal, cons i s t ing of t r a n s i e n t r i s e i n water l e v e l s , occasional breakers t o higher than normal l e v e l s , and l o c a l f looding of low a r e a s ...[ and] t h a t no l a r g e breaking wave o r bore is l i k e l y t o occur a t t h e i s land ." H I STORY Johnston A t o l l has had a var ied h i s t o r y . From two smal l , in- s i g n i f i c a n t i s l ands , t h e a t o l l has grown i n t o a l a r g e Department of Defense complex. Previous h i s to r i ca l . accounts have been w r i t t e n by Bryan (1942), Thorp (1960), and Bauer (1965). Major sources of information f o r t h i s h i s t o r y of Johnston A t o l l were t h e Bernice P. Bishop Museum Library , Hawaii S t a t e Archives, Hawaii S t a t e Library , Hawaiian Mission Children 's Socie ty Library , Hawaii H i s t o r i c a l Society Library , Library of Congress, Library of t h e National Museum of History and Technology of t h e Smithsonian I n s t i t u t i o n , U . S . Nat ional Archives, U.S. Naval Archives, and t h e Univers i ty of Hawaii Library. The s t a f f s of a l l these i n s t i t u t i o n s were most h e l p f u l , and t h e i r con t r ibu t ions a r e hereby acknowledged. Although these sources were c a r e f u l l y searched, none of them was exhausted f o r information. What i s presented here should, however, Tide Gsae Record Showing Tau~uni JOHNSTON ISUND ! Hours C.C.T. 22 23 0 ! 2 4 --ad"." . 3 5 Figure 28. Tidal wave records, Johnston Atoll CWennekens, 1969). provide a reasonable s t a r t i n g poin t f o r anyone preparing a d e f i n i t i v e h i s t o r y of t h e a t o l l . A f r u i t f u l source of information f o r r ecen t h i s t o r y , which we sca rce ly tapped, i s t h e few thousands of m i l i t a r y and c i v i l i a n personnel who have spent t ime on Johnston Ato l l during t h e l a s t 40 yea r s . Discovery and Early Explorat ion Nowhere have we found any evidence o r suggest ion t h a t Johnston A t o l l was inhabi ted or even v i s i t e d by Polynesians. Habi ta t ion would hard ly have been poss ib l e , and any v i s i t s t h a t may have occurred l e f t no mark upon the i s l a n d s t h a t was discerned by l a t e r v i s i t o r s . The Spanish s a i l e d Central. P a c i f i c waters f o r two and a half c e n t u r i e s before any s igh t ings of Johnston A t o l l a r e known t o have been recorded. Annual t r i p s i n t h e t r a d e winds from Acapulco t o Manila (between 13' and 1 4 " N l a t i t u d e ) took them l e s s than 200 mi les south of t h e Atol.1. The r e t u r n rou te , i n t h e p reva i l ing w e s t e r l i e s , took them nor th , not only of Johnston but of t h e e n t i r e Hawaiian Archipelago. Dahlgren (1916) and Stokes (1939) thoroughly explored t h e p o s s i b i l i t y of Spanish discovery of t h e Hawaiian Archipelago, a myth t h a t grew and spread from seve ra l sources but i s negated by both these au thors . We have not seen Dahlgren's paper , but Stokes conta ins no h i n t of anything t h a t might have been Johnston A t o l l . Stokes does not e n t i r e l y d iscount th.e p o s s i b i l i t y of a s i g h t i n g of t h e Hawaiian I s l a n d s by o t h e r than Spanish, s ince they were not t i e d t o t h e t r ad ing r o u t e s a s were the Spanish. The junior author perused a number of maps i n t h e Map and Cartographic Divis ion , Library of Congress, f i nd ing only two poss ib l e i s l a n d s t h a t could have been Johnston. These were t h e Basse de V i l l a Lobos, which appears on Arrowsmith Chart of 1798, and I z l e S o l i t a i r e , on a 1706 map by Goda l l e t t . Pos i t i ons of t hese were too crudely determined t o g ive any c e r t a i n t y a s to exact l o c a t i o n s , and no d e s c r i p t i o n s could be found of e i t h e r of these. It i s poss ib l e t h a t a s igh t ing of Johnston could have been respons ib le f o r t h e p lac ing of t hese i s l a n d s on t h e c h a r t s , but t h e r e i s no evidence t h a t such was t h e case , o ther than t h a t they appear i n t h e general. a r e a . The discovery of Johnston is usua l ly a t t r i b u t e d t o HMS CORNWALLIS, Captain Charles James Johnston, on 1 4 December 1.807. A t l e a s t one account of t h e i s l a n d , by Captain Joseph Pierpont of t h e SALLY, out of Boston, predated t h e CORNWALLIS s i g h t i n g by I1 yea r s , and IZrusenstern (1811) declared t h a t t h e Spaniard Don Jose Comisares saw t h e a t o l l i n 1786, 21 years before t h e CORNTJAT>LIS s i g h t i n g , The Comisares' s i g h t i n g i s poorly documented, but t h e 1796 grounding of t h e SALLY and the PRINCE WILLLAM HENRY was reported i n s e v e r a l newspapers and i s here regarded a s t h e e a r l i e s t account of t h e a t o l l on record , Captain Joseph Pierpont of t h e SALLY published t h e following no te i n seve ra l newspapers, including t h e Columbian Cent ine l of Boston on 24 June and 13 September 1797. It i s h e r e copied from Ward (1967: 417) : I n l a t . 16,45 N. long. 169,38W.from London, on my passage from t h e Sandwich I s l ands t o China; t h e 2d of Sept. 1796, a t midnight, i n company wi th t h e schooner P r ince William Henry, William Wake, Master, of London, we both ran ashore on t h e south s i d e of a reef of c o r a l rocks and sand, where we continued u n t i l next day noon -- a t which time t h e weather being very c l e a r . We saw two small i s l a n d s of sand, bearing W. by N. 4 o r 5 mi les d i s t a n t , and from our topgallant-mast- head. We saw t h e shoa l extending E .S .E . sou the r ly round t o W.S.W. -- but how f a r we were n o t a b l e t o determine. Keep t h e Lat . 17 N . and t h i s shoal w i l l not be seen. Joseph Pierpont N.B. It i s hoped t h a t t h e p r i n t e r s of America, w i l l g i v e t h e above a p l ace i n t h e i r papers. Krusenstern himself (1811: 288) suspected t h e presence of land i n t h e v i c i n i t y of Johnston A t o l l i n 1804: On t h e 15th of June we saw i n l a t . 1 7 ' and long. 169'30' a n ex t raord inary number b i r d s t h a t hovered round t h e sh ip i n f l o c k s up upwards of a hundred; t h i s r a i s e d our hopes of meeting with land very considerably; but al though t h e n igh t was p e r f e c t l y c l e a r and we kept a good lookout , t h e r e was none t o be percieved. I cannot; however, but t h ink , t h a t during t h e n i g h t , we must have passed near some i s l and or rock , s tanding above water , t h a t s e rves a s a r e s t i n g p l ace f o r these b i r d s , f o r we again saw seve ra l t h e next morning, nor d id we l o s e s i g h t of them u n t i l noon. The CORNWALLIS s igh t ing was announced by L t . %mhn. Henry Smyth, an o f f i c e r on t h e sh ip . He placed t h e i s l a n d s a t 16'53'20" N , 169?31'30" W. The s h i p ' s log described t h e i s l a n d s a s "Two very low i s l a n d s having a dangerous reef t o t h e eastward of them, and the whole n o t exceeding four mi l e s i n extent" (Xarshal l , 1827: 173). Otto von IZotzebue (1821.: 258-259), another Russian exp lo re r , de- s c r ibed t h e i s l a n d s but i t i s doubt fu l i f he a c t u a l l y saw them: The i s l a n d s which M r . Johnstone [ s i c ] discovered i n 1807, on board the f r i g a t e Cornwallis, i n t h e W,S.W. of t h e Sandw<.ch I s l ands , and which we looked f o r i n t h e spr ing of 1817, a r e , l i k e t h e i s l and of Sala y Gomez, p e r f e c t l y naked rocks which do not seem t o belong t o t h e formation of low i s l ands . The r e e f s which a r e un i t ed t o them form shoals extending t o g rea t d i s t a n c e s from them, which a r e very dangerous t o v e s s e l s t h a t naviga te these seas . No f u r t h e r s igh t ings of t h e i s l a n d s a r e known betrueen t h e p o s s i b l e Rotzebue s igh t ing of 1817 and t h a t of one of t h e sh ips of t h e Wil-kes Expedition i n 1841. (Wilkes, 1844, 5: 288): M r . 1<1iox [S.R. icnox, Acting Master of t h e U.S. Schooner FL,I!ING FISR] reported t o me t h a t a f t e r h i s s epa ra t ion , on rlle 30th of November [1841~], he stood f o r t h e p o s i t i o n of Cornwal.lis I s l and , a s l a i d dorm by Arrorusmith i n :Longitude l.69?3:L'1\'. , l ~ a t i t u d e 1 . 6 ? 5 0 ' ~ . , without seei.ng any ind ica t ion of land . Twenty-two mi les t o t h e south-by- e a s t of th:i.s ]?osii: ioi~, 11e discovered a r e e f , ruh:i.ch surrounded a11 exr:ens:Lve lagooii, extending nor th -eas t and southwest t e n mil.es, and i~? t h e oppos i te d i rec t io i l f i v e mi les . On the northwest s i d e oE t h i s reef t h e r e a r e two low i s l e t s : the one to the westward was covered wjtli hushes, b u t no Crees; the o t h e r was no more than a sand bank. T b i s reef Lies deep, The longi tude of t h e westernmost i s l e t was foui~d t o be 169"4S136" W., and t h e l . a t i tude L6?48' ii. Guano Period T11i.s s ec t ion i s taken pri.1nari.l.y from sources i n the U . S . National. Archives, Itecord Group 59, U.S. Department of S t a t e , Guano 1 .e t te rs . The next known poss ib l e s igh t ing of t h e i s l and was by William 13, Parker , capta in of t h e REINDEER, who passed througli the a rea i n January :L852 on a t r ad ing voyage t o t h e Ladrone I s l ands and China, and l a t e r claimed t o have seen s e v e r a l i s l a n d s a t Johnston A t o l l . Ifliat he actual3.y saw i s d i f f i c u l t t o determj-ne, because h i s descr ip- t i o n s f i t nothing a c t u a l l y p resen t . It i s poss ib l e he saw noth ing , but knowing i s l a n d s had been descr ibed i n t h e a r e a , made up a good- sounding s t o r y . Af ter t h e U . S . Congress passed t h e Guano Act 18 August 1856, Parker attempted t o claim t h e is3.ands under t h e a c t . On 26 August 1857 he formed a pa r tne r sh ip wi th a t t o r n e y Richard F. Ryan, of San Francisco, g iv ing Ryan one ha l f of a l l p r o f i t s from discovery. On 29 August Ryan wrote Secre tary of S t a t e Lewis Cass, g iv ing n o t i c e of paricer's discovery and asking prompt a c t i o n on t h e i r claim t o t h e i s l a n d s . The p e t i t i o n was refused on grounds t h a t Parker and Ryan were not occupying t h e i s l a n d s and could not f inance t h e i r e x p l o i t a t i o n . On 19 November Ryan submitted an a n a l y s i s of t h e guano t o t h e S t a t e Department. This s t a t e s : "The guano on Cornwallis I s land i s of ex t raord inary good q u a l i t y , c o n s i s t s of 82.53 of Azote [ni t rogenous m a t e r i a l ] i n 100 p a r t s and 17.47 of Hydrogen, t h e d e p o s i t s a r e l a r g e and from i t s dryness i s most va luab le a s an a r t i c l e of conunerce." The source of t h i s guano, or i t s r e p o r t , sound suspic ious , f o r t h e r e was no mention t h a t Parker a c t u a l l y landed on these i s l a n d s i n 1852, and no one had been back. On 19 December 1857 Parker and Ryan made an agreement with Robert G. Byxbee and Asa B. Stoddard, owners of t h e 100-ton schooner PALASTINE, g iv ing t h e sh ip owners f ive-e ights i n t e r e s t i n t h e ven tu re , they i n turn agree ing t o send t h e sh ip t o t h e i s l a n d s t o claim them and t o b r ing back a load of guano. On 20 December Ryan dispatched another l e t t e r t o Cass, enclosing an amended dec lara- t i o n of ~ a r k e r ' s c laim, s t a t i n g t h a t a v e s s e l was to be sen t f o r a load of guano i n 2 weeks. It a l s o pointed o u t t h e p o t e n t i a l importance of t h e i s l a n d s t o t h e United S t a t e s a s a coa l ing s t a t i o n . The PALASTINE departed San Francisco 8 January, under Captain William R . Perriman, and with Parker on board. They a r r ived on t h e i s l and 9 March 1858, and l e f t 1 6 March, a r r i v i n g back i n San Francisco 22 Apr i l . Subsequent s ta tements , most of them sworn and notar ized , var ied g r e a t l y a s t o exact procedures on landing . Parker ' s s tatement , dated 28 A p r i l 1858, s t a t e d t h a t he and Rich, t h e mate of t h e PALASTINE, and two seamen went ashore on Johnston I s l and and erected a f l a g s t a f f wi th a c r o s s on top wi th t h e i n s c r i p t i o n " t h i s i s l and was taken possession of by W.R. Perriman, master of t h e schooner P a l a s t i n e on behalf of t h e owners and c h a r t e r e r s of t h e schooner P a l a s t i n e i n t h e name of t h e United S t a t e s of America, James Buchanan, Pres ident . " He took l a t i t u d e and longi tude 16'46'N, 169"28'W, and with t h e mate explored t h e i s l and and took 1 3 "gunny bags" of guano (about 1,200 pounds). They a l s o landed on Sand I s l and ( ca l l ed by him Agnes, f o r h i s daughter ) , and erec ted a f l a g s t a f f with a s imi l a r i n s c r i p t i o n a s t h e one placed on Johnston Is land . Parker described t h e i s l a n d s q u i t e accu ra t e ly i n h i s s tatement and gave t h e p o s i t i o n a s 16O46'N, 16g028'W. The signed statement dated 1 May 1858 by Perriman and Rich d id not d i f f e r s i g n i f i c a n t l y from t h a t of Parlcer but added t h a t t h e r e was no s ign of previous occupation. It too gave a good d e s c r i p t i o n (ne i the r d e s c r i p t i o n , however, mentioned b i r d s ) and t h e pos i t i on given d i f f e r s only s l i g h t l y from t h a t given by Parker . Pos i t i on given i n t h e va r ious l e t t e r s and statements a l l tended toward minor v a r i a t i o n s , some of which probably r e s u l t e d from a c t u a l v a r i a t i o n s i n measurements, and some from mistakes i n copying. The most s i g n i f i c a n t p a r t of t h e s tatement , f o r l a t e r ques t ions of ownership, was: " . . . t h a t possession was immediately taken of t h e sa id i s l a n d s by t h e deponents Perriman and Rich i n company wi th t h e said Parker , and same were occupied by them dur ing t h i s time." I n May, Ryan and Louis Blanding (an a t t o r n e y fo r t h e group) cor- responded wi th Secre tary of S t a t e Cass, c a l l i n g a t t e n t i o n t o ~ a r l c e r ' s c laim and g iv ing n o t i c e t h a t a sh ip had been s e n t , guano removed, e t c . , and inc luding t h e sworn s tatements of Parker and of Perriman and Rich. On 8 June, Byxbee, Stoddard, and Ryan, toge ther with William Thompson and Cornel ius L. P lace , formed t h e P a c i f i c Guano Company, incorporated under Ca l i fo rn ia law. Parlcer was not included, but apparent ly he owned s tock i n t h e company, f o r records dated between 26 June and 6 November of 1858 show t h a t he so ld a t o t a l of 80 shares of s tock i n i t t o f i v e d i f f e r e n t people. Meanwhile, a second at tempt was made t o claim t h e i s l a n d , t h i s time f o r t h e Government of t h e Kingdom of Hawaii. Samuel C . Allen, recorded a s being from Honolulu and from San Francisco, obtained from King Kamehameha 1 V a roya l commission dated 31 May 1858 to take pos- s e s s ion of unclaimed i s l a n d s i n t h e name of t h e King. Aboard the KALAMA, under Capt. Watson, he a r r ived a t Johnston A t o l l 1 4 June, and according t o a sworn s tatement by Edward Watts, a cook and steward on t h e KALAMA, Allen and t h e Captain removed t h e f l a g s t a f f and c r o s s put up by t h e PALASTINE crew, and presumably destroyed these and t h e in- s c r i p t i o n s . They claimed t h e i s l ands , Cornwall is (Johnston) on t h e 1 4 t h and Kalama (Sand) on t h e 19th ; a f t e r e r e c t i n g a Hawaiian f l a g on them and tak ing a small sample of guano, they re turned t o Honolulu. Kamehameha I V formally claimed t h e i s l a n d s fo r h i s Kingdom i n a Proclamation 27 J u l y 1858, i n which i t was s t a t e d t h a t t h e i s l a n d s had been found " d e r e l i c t and abandoned," by the KALAMA crew. The PALASTINE re turned t o Johnston, a r r i v i n g 22 Ju ly and t h e crew found t h e i r f l a g s , e t c . , replaced by those of t h e KALAMA. They remained on t h e i s l a n d s 13 days, loading about 70 tons of guano, before leaving two men on the i s l and and r e tu rn ing t o San Francisco , a r r i v i n g 31 August. Meanwhile, Louis Blanding, a t t o r n e y fo r t h e P a c i f i c Guano Company, wrote on 13 August t o James W . Borden, U.S. Commissioner i n Honolulu, asking Borden to inform t h e Hawaiian Government of h i s company's p r i o r claim t o t h e i s l a n d , and reques t ing "some p o s i t i v e disapproval of the a c t . " The company had most l i k e l y heard of t h e t r e spass v i a t h e King's proclamation i n Honolulu, s i n c e t h e i r sh ip had not y e t re - turned when t h e l e t t e r was w r i t t e n . On the r e t u r n of t h e sh ip , Blanding wrote Lewis Cass, U.S. Secre tary of S t a t e , informing him of t h e d e t a i l s of t h e t r e s p a s s by t h e KALAMA, and p lac ing t h e blame on t h e crew of t h e KALAMA, s t a t i n g t h a t t h e King probably d id not know of the p r i o r claim a t t h e time he issued h i s proclamation. When the Hawaiian Government was informed of t h e f a c t s , v i a d ispa tch from Commissioner Border, 8 September, A l l en ' s r o y a l com- mission was rescinded a s f a r a s Johnston I s l a n d s were concerned, and i t was amended t o t h e e f f e c t t h a t t h e commission was void i n cases of p r i o r claim by o t h e r powers. This had been t h e i n t e n t of t h e o r i g i n a l commission, but i t was not s p e c i f i c a l l y worded. The King then s o l i c i t e d from Borden an opinion a s to whether t h e f l a g , c r o s s , and i n s c r i p t i o n s l e f t by t h e PALASTINE'S crew 9 March f u l f i l l e d t h e requirements f o r claims under t h e Guano Act. This a c t requi red t h a t t h e i s l a n d s be occupied by t h e claimant or t h e i r agents . Byxbee, Pres ident of t h e P a c i f i c Guano Company, had requested s i m i l a r information from Cass i n a l e t t e r dated 19 August 1858 reques t ing a s tatement a s t o t h e v a l i d i t y of Pa rke r ' s c laims and t h e means by which a l l requirements of t h e Guano Act could be met. On 9 November t h e Hawaiian Government requested Borden t o a s k t h e P a c i f i c Guano Company not t o send v e s s e l s t o t h e i s l a n d s t o load guano, adding t h a t t h e Hawaiian Government was asking t h e same of Allen, u n t i l ownership had been s e t t l e d , t o avoid a conf ron ta t ion by t h e two p a r t i c i - pants on t h e i s l a n d . Newspaper a r t i c l e s a t t h e time i n d i c a t e t h e King re l inquished claim t o t h e i s l a n d , but our search has not produced t h e a c t u a l documents. A confronta t ion did occur , however, f o r Allen sen t Captain Borland i n t h e sh ip GAUNTLET t o t h e i s l and f o r a load of guano. On a r r i v a l , he found t h e two P a c i f i c Guano Company men i n possession of t h e i s l and and t o l d them he intended to load the GAUNTLET, us ing f o r c e , i f necessary. The P a c i f i c Guano Company had i n t h e meantime sen t A.D. P iper i n the sh ip MIANT, under Captain Hallet t , t o take command of t h e i s l a n d and t o prepare f o r shipping guano. The GAUNTLET was a t anchor when Piper a r r i v e d and he immediately p ro te s t ed i t s presence t o Borland, but o f f e red t o s e l l him a load of guano a t $4.00 per ton , or t o cha r t e r h i s sh ip f o r h i s own firm--the P a c i f i c Guano Company. Borland apparent ly was more in t imidated by t h e d i f f i c u l t i e s i n loading from t h e i s l a n d s than by t h r e a t s o r d e a l s , s o he accepted n e i t h e r o f f e r . Captain H a l l e t t concurred t h a t loading was impossible , and refused t o load t h e RADIANT. Both Borland and H a l l e t t then l e f t t h e i s l a n d , l eav ing Piper and 11 men i n armed possession of t h e i s l a n d . Piper s e t h i s men t o work preparing a wharf, ra i lway, e t c . , f o r shipping guano. The FENIMORE COOPER, under Captain John M . Brooke, was ordered t o t h e i s l and i n March 1859, to survey t h e i s l a n d s and make soundings. He a r r i v e d 1 4 March and learned t h e above s t o r y from Piper (Brooke, m s ; s e e a l s o , Brooke, 1955). Meanwhile, i t appeared t h a t Parker was being squeezed out of t h e Pa r tne r sh ip which had become t h e P a c i f i c Guano Company. The company had pursued t h e claim, through p r o t e s t s over t h e i n t r u s i o n by Al l en ' s s h i p s from Honolulu, and by l e t t e r s t o t h e S t a t e Department reques t ing information a s t o proper means of complying with and f u l f i l l i n g t h e requirements of t h e Guano Act. I n support of t h e content ion t h a t Parker himself had no claim t o t h e i s l a n d s , Perriman and Rich again on 25 and 26 October 1858 made sworn s tatements a s t o t h e happenings on t h e f i r s t landing on t h e i s l a n d s i n March. They s t a t e d t h a t Parlcer had sa id t h e r e was but one l a r g e i s l and wi th t r e e s on i t , which was v i s i b l e on t h e horizon f o r 20 mi l e s , and which had no r e e f s around i t . What they found ins tead a f t e r bea t ing about f o r 7 days, was t h e two small i s l e t s , v i s i b l e only 8 mi l e s , with no t r e e s , and wi th ex tens ive dangerous r e e f s a l l around. There i s suspic ion t h a t t h i s s t o r y was a t l e a s t i n p a r t concocted, because P a r k e r ' s o r i g i n a l c laims described no l e s s than 7 i s l a n d s and i s l e t s , some sa id t o be no more than cays; i t i s t h e r e f o r e not too l i k e l y t h a t he would have t o l d Perriman t h e r e was only one i s l and while they were searching f o r them. Perriman f u r t h e r claimed t h a t he and two o the r s went ashore on Johnston a t 0900 on t h e f i r s t day, and t h a t Parker d i d not land u n t i l t h e second boat i n t h e af ternoon. I n h i s f i r s t s tatement , Perriman sa id he and Rich ". . . i n company xrith.. .Parker . . ." had taken possession of t h e i s l a n d . Here he a s s e r t s t h a t Parker was not along on t h e f i r s t l anding , al though he does not say what p a r t Parker had i n t h e claiming ceremonies. I n t e r e s t i n g l y , i n a newspaper in te rv iew i n 1892, 34 yea r s a f t e r t h e f i r s t landing, Perriman as se r t ed t h a t Parker d i d not go ashore a t a l l . Who was t ry ing t o p u l l what on whom i n t h e h a s s l e t h a t took p lace over t h e claim t o t h e i s l and is not c l e a r from t h e a v a i l a b l e documents. Parker may not have even seen t h e i s l a n d s before t h e f i r s t PALASTINE t r ip- -h is d e s c r i p t i o n s up t o t h a t time c e r t a i n l y d id not f i t any e x i s t i n g i s l ands . Whether t h e organizers of the P a c i f i c Guano Company were t r y i n g t o g e t r i d of him a s a par tner i n t h e bus iness , or whether he was t r y i n g t o u s e t h e company a s a means f o r claiming t h e i s l a n d s f o r h imsel f , or both, is not c l e a r . But t h a t both were occurr ing s imultaneously i s not out of t h e quest ion. I n any case , by 6 November 1858 Parker had so ld a l l h i s ownings i n t h e company--80 shares . On 22 February 1859 Parker died i n a h o t e l i n Washington D . C . , supposedly t h e r e t o p e r f e c t h i s claim t o t h e i s l ands . Pa rke r ' s supposed widow, Har r i e t B. Parker , pursued h i s claim t o t h e i s l a n d s , but a j u d i c i a l r u l i n g from Jeremiah Black, l a t e r i n 1859, s t a t e d t h a t s ince Parker had not a c t u a l l y occupied t h e i s l a n d s , and t h e P a c i f i c Guano Company had, t h e company was t h e proper possessor of t h e i s l ands . Consequently t h e company posted bond f o r $100,000.00 f o r r i g h t s t o e x p l o i t t h e i s l a n d . I n 1859 a t to rneys f o r Pa rke r ' s h e i r s and f o r t h e P a c i f i c Guano Company wrote seve ra l l e t t e r s t o t h e Secre- t a r y of S t a t e and t o Pres ident Buchanan at tempting t o v e r i f y t h e i r claims. The amount of guano being taken off during 1859 and subsequent years must have been f a i r l y s u b s t a n t i a l , i f t h e number of sh ips and t h e s tatements of t h e i r cap ta ins can be t r u s t e d . There is, however, some quest ion a s t o t h e va lue of t h e product shipped. It was reputed by a t l e a s t two sh ip capta ins t o be of h igh q u a l i t y , e a s i l y obtained, e t c . , but Hague, i n 1862, wrote t h a t : "...from Johnston 's I s l ands one or two cargoes have been brought t o t h i s country [ t h e United S t a t e s ] , t h e g r e a t e r p a r t of which proved, I b e l i e v e , t o be sand. These a r e described a s t h r e e small i s l a n d s (probably i s l e t s of one a t o l l ) con- t a in ing but l i t t l e guano and t h a t mixed with c o r a l sand." Whether t h e companies continued i n content ion i s not known, but they probably d i d , f o r sh ips of t h e American Guano Company were repor ted i n and out of Honolulu t o and from Johnston Is land i n 1860 and 1861. The C i v i l War caused an i n t e r r u p t i o n i n both guano e x p l o i t a t i o n and i n a t tempts t o pursue claims, but s h o r t l y a f t e r i t was over , ~ a r k e r ' s only h e i r s , h i s widow H a r r i e t B. Parker and t h e i r daughter Agnes Parker Bur t t ( fo r whom Agnes I s l a n d , now Sand I s l and , was named by Parker) aga in took up t h e claim of t h e guano i s l ands . William H. Parker , Jr., ~ a r k e r ' s only son, had d ied of wounds suf fered while serv ing wi th t h e Union Army a t Antietam. I n 1872, ~ a r k e r ' s widow was successfu l i n g e t t i n g Congress t o amend t h e Guano Act t o a l low l e g a l h e i r s t o claim i s l a n d s of deceased o r i g i n a l c laimants . She had no success , a s f a r a s is known, i n ob- t a in ing c l e a r t i t l e t o t h e i s l ands , or any compensation f o r whatever guano was removed. Their p r i n c i p a l c la ims were t h a t a document awarding t h e i s l a n d s t o the P a c i f i c Guano Company bore t h e forged s igna tu re of Secre tary of S t a t e Cass; t h a t Parlcer was a c t i n g alone i n clajrning t h e i s l a n d s ; t h a t he had not so ld s tock i n t h e P a c i f i c Guano Company; and t h a t Perriman and Rich made statements i n October r.711ich c.onfl.icted with those made i n May i n order t o he lp t h e Company beat Parker out of h i s c l a i ~ n . About 1879 a t h i r d h e i r appeared. M r s . Ma1.vi.na 13. Parlcer, of San Francisco, who cl-aiined to have been married t o W,Fi.. I'arlcer 16 July 1858 i n San. Francisco , and furnished proof i n t h e form of sworn s t a t e - nienis by t h e J u s t i c e of t h e Peace who performed t h e cereiilony. She, together x,7it.h Agnes J?arker Bur t t , disclai.med tile a s s e r t i o n s by liarriel: 8 . Parlcer, whom they nor? r e fe r r ed t o a s J i a r r i e t R. Fishe r , of her r i g h t s t o t h e guano isl.ands cl.ai111s. ApparentlLy Parker had divorced Har r i e t R . Parker sometime before 1.858. Records of t h i s were not searched f o r , but probably could be :found. Hal~vina 1.1. Parlcer a c t u a l l y sold heir c1aiins t o t h e isl-and t o a man named Hueston, of Michigan, who j~n turn sold i t back t o he r . Ships kno\.nl t o s top a t .Johnstoi? I s l~aud a f t e r t h e Civi.1. War were few. Presumably most of these stopped fo r guano, but a s f a r a s i s knox,m, t h e r e Tias no permanent, coi~t i i luous occupancy ducing t h i s time. The only major shi.p~.xecb kn0x.m to have. occurred on t h e a t o l l happened i n 1889. This i s reniar1cabl.e i n view of tile diff : icul . ty i n seeing t h e i s l a n d , and t h e number of whalers, guano s h i p s , e t c . , plying these wa.ters throughout t h e 18 th and 19th c e n t u r i e s . The ~ihal.er 3-13. 1:IOWLAND r.xeciced on t h e isl-and 26 December L889. One or two men were l o s t i n g e t t i n g t h e men ashore over t h e coral. heads of t h e lagoon. A l l sur- v ivo r s were subsequently picked up and re turned t o Hawaii. In 1892 Great B r i t a i n attempted t o claim Johnston a s a p o t e n t i a l cable s t a t i o n . HHS C1M4.PION was dispatched from Honolulu with orders t o h a v e f o r t h e isl-and without te l - l ing anyone where they were headed. This they d i d , and f ind ing t h e i s l and to t a l - ly abandoned, claimed i t f o r Great B r i t a i n . The CHAMPION'S capta in described t h e i s land and made a small ske tch map of i.t--quite accu ra t e f o r ;ohnston, but crude f o r Sand which they saw only from a d i s t a n c e . They a l s o found remains of t h e ~ . x e c l a g e of t h e whaler. On Learning of t h e B r j ~ t i s h claim, an agenc, Lomberg, f o r the P a c i f i c Guano Company claimed t h e company had not given up possession of t h e i s l a n d s , and expected t o r e t u r n t h e r e t o resume opera t ions , and a l s o expected p r o t e c t i o n by t h e United S t a t e s Government. There a r e no records i n d i c a t i n g t h a t t h e company did r e t u r n t o t h e i s l ands . The S t a t e Department, however, sti.11 l i s t e d Johnston a s an i s land bonded t o t h e U.S. a s l a t e a s 1893. I n 1905 t h e r e was renewed i n t e r e s t by Pa rke r ' s h e i r s . Mrs. Agnes Parker Bur t t York, Parlcer's daughter , i n agreement wi th William H. Underwood and LeGrande Brown,visited t h e is1.ands aboard t h e Steamer IWILANI 14 February 1905 and brought off a small cargo of guano. Shor t ly a f t e r t h i s v i s i t , M r s . York sold t h e i s l a n d s t o Underwood f o r $250,000.00, most of which was t o be paid from a 10 percent roya l ty on a l l guano so ld . On 9 June 1905 Underwood sold t h e i s l a n d s t o Phineas Coleman f o r $1.00 p lus unnamed "cons idera t ions ." On 3 August Coleman so ld t h e i s l a n d s t o t h e United S t a t e s Guano Company f o r $10,000,000.00. Whether Mrs. York had a c l e a r t i t l e t o t h e i s l a n d s before she sold t o Underwood, o r i f any money a c t u a l l y changed hands i n these d e a l s i s not known. Furthermore, a s f a r a s i s known, no f u r t h e r sh ips were sen t out by any of t hese p a r t i e s . I n 1909 t h e T e r r i t o r y of Hawaii leased t h e i s l a n d s t o Max Schlemmer, of Honolulu, f o r 15 yea r s (Govt. l e a s e #661, 20 September 1909, f i l e d with o f f i c e of Commissioner of Public Lands, T e r r i t o r y of Hawaii). Johnston had n o t , however, been included i n t h e T e r r i t o r y of Hawaii when t h e l a t t e r was annexed by t h e United S t a t e s on 30 Apr i l 1900. Schlemmer never removed guano nor did he f u l f i l l t h e requirements of h i s l e a s e , which included p lan t ing 500 coconut t r e e s per annum and maintaining them throughout t h e l e a s e . During June 1914 Captain George P l i l t z , i n company with Edward M. May, v i s i t e d t h e a t o l l and found i t t o be uninhabited and unimproved wi th no s ign of coconut t r e e s . Con- sequently, i n 1918 t h e l e a s e was voided, and another l e a s e was given t o C.IZ. A i , of Honolulu, whose Japanese f i rm, C.K. A i and Company, proposed t o use t h e i s l and a s a f i s h i n g s t a t i o n . H i s p a r t y of Chinese s tayed on t h e i s l and only one day, however, be fo re they mutinied and re turned t o Honolulu. The f i r s t s c i e n t i f i c expedi t ion t o v i s i t t h e i s l a n d s , excepting t h e poss ib l e v i s i t by t h e Wilkes sh ips i n 1841, and t h e surveying done from t h e FENIMORE COOPER i n 1859, was done by t h e pa r ty v i s i t i n g t h e i s l a n d s aboard t h e minesweepers TANAGER and W1-IIPPOORWILL i n Ju ly 1923. This p a r t y was headed by Alexander Wetmore, then of t h e Bureau of Bio logica l Survey of t h e Department of Agr icul ture , l a t e r t o become Secre tary of t h e Smithsonian I n s t i t u t i o n . Other members of t h e ex- ped i t ion represented t h e Bernice P. Bishop Museum of Honolulu. Their s p e c i a l i n t e r e s t s and t h e published r e s u l t s of t h e i r t r i p a r e discussed under t h e Biota sec t ion i n t h i s r e p o r t . Commander John Rodgers, l a t e r t o become famous f o r seaplane f l i g h t from Ca l i fo rn ia t o Hawaii, and two o the r a v i a t o r s were along and made a e r i a l photographs of t h e i s l a n d s and r e e f s with t h e a id of a small seaplane . The pa r ty was on t h e i s l a n d s from 10 through 20 J u l y 1923. Because of t h i s v i s i t , t h e a t o l l was made a f e d e r a l b i rd re fuge on 29 Ju ly 1926 by Executive Order No. 4467 of Pres ident Calvin Coolidge and placed under con t ro l and j u r i s d i c t i o n of t h e Department of Agricul- t u r e . I n 1940 t h i s r e s p o n s i b i l i t y was t r ans fe r r ed t o t h e U.S. Department of I n t e r i o r . This Order s t i l l remains i n e f f e c t , a l though subsequent execut ive orders have given j u r i s d i c t i o n over t h e a t o l l t o m i l i t a r y agencies (Table I ) . In 1924 t h e TANAGER and WHIPPOORWILL re turned t o t h e i s l a n d s a s p a r t of Mine Squadron Two, which included t h e LUDLOW and t h e BURNS. These four sh ips , together with the tender PELICAN$ wi th one seaplane on board, l e f t i-lonolulu 3 June 1924 and a l l but t h e PELICAN which had Table 1. Ownership and con t ro l of Johnston A t o l l (Bauer, 1965) Operational Period "Owner " Control Purpose of Document Authori ty EventfUse 1923 Dept. of Agric. Agric. P l an t and s e a l i f e Exec. Order 4467" Bird re fuge (Exec. Order surveys June 29, 1926) ( see a l s o Anon., 1926) 1934 Dept. of Navy USN P a c i f i c defense Exec. Order 6935" I , ,, I t USN Establ ished Naval Exec. Order 8682" Became Johnston Is land Naval Defense Sea Area f o r A i r S t a t i o n m i l i t a r y sea and a i r opera t ions 1944 11 1 1 1 , USN - -- Defense of a r e a ; A i r Trans- p o r t Command opera t ions ; Oceanic A i r T r a f f i c Control 1947 ,, 11 11 USN -- Secy. of Navy Became a Naval A i r F a c i l i t y 1948 J u l y 1 r , ,, ,, USAF Transfer of opera- Agreement P a c i f i c A i r Command (MATS, t i o n a l c o n t r o l to ARS, AACS, AWS Dots) (Secy. USAF Navy ordered t r a n s f e r t o USAF 1949 June 1 11 ,, 1 1 USAF 1951-52 1 1 1, 11 USAF 1957 Jan. 25 " " " USAF 1957 S e p t . 1 3 " " " USAF P a c i f i c A i r Command inac- t i v a t e d ; P a c i f i c Divis ion MATS took over Korean a i r l i f t support USAF granted Treasury De- partment f i v e year u s e f o r USCG L O W S t a t i o n C- USAF granted Department of + Commerce f i v e year use f o r U.S. Weather Bureau h Table 1. (continued) N Operat ional Period "Owner" Control Purpose of Document Authori ty Eventiuse 1958 Apr. 22 Dept. of Navy CJTF-7 1959 Ju ly 24 " " " USAF -- 1959 S e p t . 2 3 " " " USAF To t r a n s f e r opera- t i o n a l con t ro l t o Army 1959 June 30 " " " USAF -- 1962 J a n . 1 7 " " " CJTF-8/ AEC 1962 Jan. 18 " " " CJTF-8/ AEC 1963 J u n e 1 1 " " " C JTF-8 / AEC Agreement Atomic t e s t s i n P a c i f i c a rea u n t i l August 19, 1958; then ro l l -up -- Formal meeting i n Hawaii t o propose t r a n s f e r of opera- t i o n a l con t ro l t o Army f o r Nike-Zeus t e s t program Agreement Agreement Proposed agreement sen t t o higher headquarters Secy. of Treasury asked Secy. of Defense f o r Sand Is land a s LORAN S t a t i o n , t o be under op- e r a t i o n a l c o n t r o l of Commander i n Chief , P a c i f i c USAF signed Operations Agree- ment f o r 1962 nuclear t e s t s Commander i n Chief , P a c i f i c , signed agreement with Command- e r J o i n t Task Force Eight J o i n t Chiefs of S taf f r ea f - firmed opera t ion c o n t r o l of J o i n t Task Force Eight 1973 spr ing 1 1 1 1 71 Defense Nu- c l e a r Agency *Executive Orders a r e s t i l l i n e f f e c t ; have not been amended o r rescinded so a s t o a f f e c t "ownership." mechanical d i f f i c u l t u e s and was delayed a day, a r r i v e d off Johnston on t h e 6th. On t h e 7 t h work began i n s e t t i n g up s i g n a l s on t h e i s l a n d s f o r surveying t h e lagoon, which was done from 10 through 20 June. Accurate pos i t i on determinants were made, c u r r e n t s were s tud ied , a t i d e guage was opera ted , and extens ive soundings were made throughout t h e lagoon. Although t h e r e was no record of any s c i e n t i f i c personnel on board, c o l l e c t i o n s of c o r a l , marine growth, land s h e l l s , e t c . , were made f o r t h e Bishop Museum. Eight coconut and 12 ironwood t r e e s were planted " . . . in favorable loca t ions" on Johnston I s l and . Recommendations were made f o r use of t h e a t o l l f o r seaplanes, a s i t was thought t h a t seaplane runways could be developed e a s i l y by b l a s t i n g c o r a l heads. The s i g n a l s e rec ted on t h e i s l and were removed so subsequent v i s i t o r s , no tably t h e Japanese, would n o t know t h e survey had been made. The ex- p e d i t i o n l e f t t h e a t o l l 22 June and a r r ived back a t P e a r l Harbor on t h e 26th (U.S. Nat. Archives, R.G. 37, Le t t e r from G.V. Stewart , Commander, Mine Squadron Two, t o Chief of Naval Operat ions) . During t h e l a t e 1920's t h e i s l and was v i s i t e d by a t l e a s t one f i s h i n g v e s s e l out of Honolulu, t h e LANIKAI; Captain B i l l Anderson (who was along on t h e 1923 expedi t ion with Wetmore, and who had been on t h e i s l a n d , aga in from a f i s h i n g v e s s e l , i n November 1922) and Lor r in A. Thurston, a Honolulu r e p o r t e r , were t h e p r i n c i p a l members of t h e crew. Thurston repor ted h i s 1927 experiences, inc luding t h e f ind ing of t h e wreclcage of t h e J . B . HOWLAND, i n t h e Honolulu Adver t i ser , 5 and 26 August 1928. M i l i t a r y Occupation No f u r t h e r m i l i t a r y a c t i v i t y occurred on t h e a t o l l u n t i l 1933, when Johnston was included i n an exe rc i se i n extended reconnaissance f l i g h t s by Navy p a t r o l planes. Data obtained from t h e 1924 survey were t o be recheclced ". . .with view t o a c t u a l l y determining t h e prac- t i c a b i l i t y of u t i l i z i n g Johnston I s l and a s a temporary a i r c r a f t base" (U.S. Nat. Archives, R.G. 45, Chief of Naval Operations t o Commander i n Chief , U.S. F l e e t , 26 January 1933). The USS PELICAN l e f t P e a r l Harbor 17 A p r i l 1933 and a r r i v e d o f f Johnston 20 Apr i l . A small boat attempted t o en te r t h e lagoon through a r e e f b l a s t ed through t h e r ee f west of Johnston I s l and by t h e 1924 expedi t ion , but was unsuccessful because of h igh s u r f . Entry was made around t h e southwest end of t h e r e e f , and landing and mooring a r e a s f o r seaplanes were searched f o r i n v a i n i n t h e west and north- west p a r t s of t h e lagoon. On t h e 21st a despe ra t e at tempt was made t o f i n d s u i t a b l e mooring a r e a s , and f i n a l l y t h e a rea between Johnston and Sand I s l ands was picked and a message sent out t o t h a t e f f e c t . Meanwhile, a squadron of seaplanes had l e f t Hawaii and flown t o French F r i g a t e Shoals, fol lowing a l i n e of sh ips spaced a t i n t e r v a l s along t h e rou te . Af ter t h e planes a r r ived a t French F r i g a t e Shoals, t h e sh ips rea l igned themselves between t h e r e and Johnston A t o l l , and on 22 A p r i l four p lanes l e f t f o r Johnston, a r r i v i n g a t noon. The only adverse inc iden t was t h e s t r i k i n g of a l a r g e b i rd by one of t h e planes a s i t landed. The damage was repa i red successfu l ly on t h e i s l and . A l l p lanes were fueled and serv iced and departed f o r French F r i g a t e Shoals on t h e morning of 25 A p r i l ( see Amerson, 1971). A general d e s c r i p t i o n was made, including t h e information t h a t t h e r e was no vege ta t ion except f o r "long grass ." Apparently t h e t r e e s planted i n 1924 d id not surv ive . Johnston Is land was considered long enough f o r landing small land p lanes , w i th considerable grading necessary beforehand. The presence of l a r g e numbers of b i r d s on both i s l a n d s and t h e i s l a n d s being r i d d l e d wi th holes made by t h e b i r d s were considered a s major hazards t o a i r c r a f t opera t ions , e s p e c i a l l y i f land p lanes were t o be used. It was concluded t h a t t h e a t o l l o f f e red (1 ... only f a i r p o s s i b i l i t i e s f o r making a good advanced base" (U.S. Nat. Archives, R.G. 45, l e t t e r , L t . F.M. Hughes, USN, t o Commander, A i r c r a f t Squadrons and a t t end ing c r a f t , F l e e t A i r Base, P e a r l Harbor, T.H.). Several photographs were made during t h i s opera t ion , and these a r e on f i l e i n t h e National Archives. On 18 December 1934 t h e a t o l l was v i s i t e d by t h e Coast Guard s h i p ITASCA i n a va in search f o r t h e l o s t a i r c r a f t STAR OF AUSTRALIA. Both i s l a n d s were b r i e f l y explored by Captain C.T.P. U l m and two com- panions and described very gene ra l ly by Jan Jabulka (1934), a r e p o r t e r on board t h e sh ip . Because of t h e a t o l l ' s s t r a t e g i c m i l i t a r y l o c a t i o n , Pres ident Frankl in D. Roosevelt , on 29 December 1934, by Executive Order No. 6935, placed t h e a t o l l under t h e Department of t h e Navy. Provis ion was made wi th in t h e new Order t o keep Executive Order No. 4467, thus pro- t e c t i n g t h e breeding b i r d s and h a b i t a t . I n 1935 t h e ITASCA again v i s i t e d t h e a t o l l on 23 June and 23 September. The general d e s c r i p t i o n of t h e i s l a n d s noted t h a t an old guano shed was p resen t , but l y ing f l a t , and t h a t narrow guage r a i l r o a d wheels were s t i l l present . On 12 November 1935 a squadron of 6 Navy p lanes f lew t o t h e i s l a n d s from French F r i g a t e Shoals and they re turned on t h e 13 th . I n 1936 t h e Navy began developing t h e a t o l l . By 19 October 1936 a 210-foot p i e r had been b u i l t ou t from the south s i d e of Sand I s l and and a sinuous, narrow boat channel had been opened through t h e r e e f s from t h e south i n t o t h e seaplane landing a rea northwest of Sand I s l and (see Fig. 8 ) . Reports i n d i c a t e t h a t a reconnaissance f l i g h t t o t h e a t o l l had occurred e a r l i e r i n t h e year by VP Squadron Ten. F i r s t b l a s t i n g opera t ions were c a r r i e d out by t h e advance p a r t y , and i n October t h e USS WRIGHT a r r i v e d wi th more explosives (U.S. Nat. Archives, R.G. 45, l e t t e r s of 15 October and 23 November 1936, from Commander K. Whiting, A i r c r a f t Squadrons and a t t end ing c r a f t , F l e e t A i r Base, P e a r l Harbor, T.H., t o Hydrographer). The PELICAN and TANAGER a r r i v e d on 30 March 1937, and t h e SWAN on 31 March, a l l ca r ry ing explos ives f o r en larg ing t h e channel. A s a r e s u l t of t h i s l a s t e f f o r t , t h e a r e a f o r seaplane landing and mooring was about doubled and 24 planes could be accommodated. Blas t ing was a l s o done around t h e p i e r . Recommendations were made f o r fu r the r im- provements t o al low tenders t o g e t c l o s e r t o t h e anchorage a rea or t h e planes. A map of t h e lagoon dated 14 Apr i l 1937 showed a s t r a i g h t boat channel from t h e south s i d e of t h e lagoon i n t o t h e seaplane landing a r e a , and on Sand Is land a mess h a l l was marked a t t h e northwest s i d e of t h e base of t h e p i e r , and on t h e southeas t s i d e a s i g n a l tower (U.S. Nat. Archives, R.G. 45, l e t t e r from Lt . Commander J.L. Cotton, USN, Johnston I s l and Expedition, t o Commander, Minecraft , B a t t l e Force) . On 8 A p r i l 1937 two VP-6's made a round t r i p from P e a r l Harbor t o Johnston and back i n 10 and a ha l f hours t o r e scue a s i c k seaman (Bryan, 1939). I n l a t e 1939 t h e Navy awarded a c o n t r a c t f o r cons t ruc t ion of a small base and i n October or November a f o r c e of 60 men were sent t o t h e a t o l l t o begin work on a$l,150,000.00 warplane, minec ra f t , and submarine base f o r t h e U.S. Navy, t o be completed i n a year (Anon., 1939). A t f i r s t a lagoon seaplane landing a rea with headquar te rs on Sand Is land was b u i l t . But t h i s t i n y i s l e t soon was overcrowded ( see Fig . 9 ) , and expansion i n 1940 was made t o Johnston Is land i t s e l f ( see F ig . 10) . The work, d e t a i l s of which can be found i n Woodbury (1946), was rushed and t h e Naval A i r S t a t i o n was commissioned ahead of schedule on 15 August 1941 (Bauer, 1965). On February 1 4 of 1941 P r e s i d e n t i a l Executive Order 8682 s e t up t h e Johnston Is land Naval Defensive Sea Area and Johnston Is land Naval Airspace Reservat ion t o inc lude r e s p e c t i v e l y t h e "waters between extreme high water marks i n the three-mile marine boundaries surround- ing t h e i s l a n d , and t h e a i r spaces over t h e s e waters and i s l ands . " On 15 December 1941, four months a f t e r being commissioned, Johnston Is land was she l l ed f o r 10 minutes by Japanese su r face c r a f t . Again on 21, 22, and 29 December both Johnston and Sand I s l ands were she l led from o f f shore sh ips ; one Japanese submarine was repor ted sunk by land guns. There were no i n j u r i e s t o personnel but c i v i l i a n workers were demoralized. The s h e l l i n g caused cons iderable damage t o va r ious f a c i l i t i e s ( see Bauer, 1965). Construct ion continued u n t i l A p r i l 1942; p r o j e c t s included dredging channel approaches and seaplane landing a r e a s , cons t ruc t ion of bomb s h e l t e r s , l i v i n g qua r t e r s , landplane runways, s to rage sheds, and gun emplacements. In a d d i t i o n t o being an a i r s t a t i o n dur ing e a r l y World War 11, p a t r o l submarines used t h e a t o l l a s a r e f u e l base. By 1944 and throughout t h e r e s t of t h e war, i t became one of t h e bus i e s t a i r t r ans - po r t te rminals i n t h e P a c i f i c , s e rv ic ing p lanes going t o and from t h e P a c i f i c f r o n t some 4,000 mi les t o t h e west. A t t h e end of World War 11, t h e Navy continued t h e Naval A i r S t a t i o n a t reduced s t r e n g t h but a s a c t i v i t y decreased, t h e s t a t u s was degraded t o t h a t of a Naval A i r F a c i l i t y . Sand Is land was abandoned i n 1946. By order of t h e Secre tary of t h e Navy, ope ra t iona l con t ro l of Johnston A t o l l was t r ans fe r r ed on 1 J u l y 1948 from t h e U.S. Navy t o t h e U.S. A i r Force; Navy, however, r e t a ined t e c h n i c a l j u r i s d i c t i o n . During t h e Korean a i r l i f t i n 1951 and 1952, Johnston Is land again assumed m i l i t a r y importance. The a i r s t r i p was enlarged by dredging and new bui ld ings and improved u t i l i t i e s were added. For a sho r t t ime, m i l i t a r y personnel were permitted t o have t h e i r dependents accompany them t o Johnston; t h i s ended i n October 1956. On 25 January 1957, t h e Treasury Department was granted a permit f o r t h e U.S. Coast Guard (now under t h e Department of Transportat ion) to operate a LOMN t ransmi t t ing s t a t i o n on Johnston I s l and . Also on 13 September 1957, t h e Department of Commerce was permitted to opera te a Weather Bureau S t a t i o n on t h e I s l and . On 22 A p r i l 1958 ope ra t iona l c o n t r o l of Johnston was assumed by t h e commander of J o i n t Task Force Seven. A s p a r t of Operation I-Iardtack, two m i s s i l e s car ry ing thermonuclear devices were f i r e d from Johnston I s l and i n t o t h e s t r a t o s p h e r e t o obta in information on t h e e f f e c t s of nuclear de tonat ions a t high a l t i t u d e s . Teak, t h e f i r s t of t hese sho t s , was detonated a t 2150 hours on 1 August 1958, a t an a l t i t u d e of 252,000 f e e t . The second s h o t , Orange, was detonated a t 2130 hours on 12 August a t approximately 100,000 f e e t . These were t h e f i r s t megaton devices detonated i n t h e s t r a tosphe re by t h e United S t a t e s (Nines, 1962). The P a c i f i c phase of Operation Hardtack l a s t e d u n t i l 19 August 1958. Operational c o n t r o l of Johnston was aga in assumed by J o i n t Task Force Eight (JTF-8) and t h e Atomic Energy Commission (AEC) on 17 January 1962 f o r t h e purpose of conducting a d d i t i o n a l h igh -a l t i t ude nuclear t e s t s . Shot S t a r f i s h , an explosion of about 1 . 5 megatons, was conducted a t an a l t i t u d e of 200 ki lometers on 9 J u l y 1962. Another t e s t , scheduled f o r 25 J u l y 1962 was aborted a f t e r t h e t e s t m i s s i l e was destroyed. During these nuclear t e s t s , an e l abora t e water s p r i n k l e r system was i n s t a l l e d on t h e o r i g i n a l po r t ion of Sand Is land t o p r o t e c t t h e b i r d s l i v i n g the re . I n a d d i t i o n , o ther p r o t e c t i v e devices were used, including smoke pots placed upwind a s a shade screen and a e r i a l f l a r e s to d i v e r t t h e b i r d s ' a t t e n t i o n from t h e f l a s h of t h e b l a s t i t s e l f . The Secre tary of Defense granted permission on 10 December 1959 f o r t r a n s f e r r i n g t h e U.S. Coast Guard LORAN-A and -C S t a t ion t o Sand I s l and . The Coast Guard f a c i l i t y on Sand I s l and was completed i n 1961 and p resen t ly maintains a complement of approximately 25 men. A U.S. A i r Force S a t e l l i t e Tracking Camera S t a t i o n was es t ab l i shed on Sand i n 1364. A s of 1965, Johnston A t o l l was under j o i n t ope ra t iona l con t ro l of JTF-8 and AEC. It serves a s headquarters and base of opera t ions f o r resuming U.S. atmospheric nuclear t e s t i n g i n t h e P a c i f i c should t h e Test Ban Treaty of 1963 be n u l l i f i e d by a fo re ign world power. Tenants on Johnston Is land included: U.S. A i r Force and Navy u n i t s , and personnel of t h e A i r Defense Command, Space Systems Command, and P a c i f i c M i s s i l e Range. I n t h e e a r l y 1970's va r ious chemical agen t s , inc luding herb ic ides l e f t over from t h e Vietnam C o n f l i c t , were brought from t h e western P a c i f i c and s tored on Johnston I s l and . These were placed downwind i n a s e c u r i t y a rea on t h e southwest end of t h e i s l and . A s of 10 May 1974 measures were being considered by t h e Environmental P ro tec t ion Agency t o s a f e l y d ispose of t hese agents . I n t h e spr ing of 1973, ope ra t iona l con t ro l of Johnston A t o l l came under t h e Defense Nuclear Agency. The a t o l l i s s t i l l a Naval Defensive Sea Area and A i r Space Reservat ion, and access i s r e s t r i c t e d . The a t o l l i s a b i rd sanctuary under t h e Department of I n t e r i o r . BIOTA The following treatment of ~ o h n s t o n ' s b i o t a does not t r e a t taxa evenly. Some a r e e n t i r e l y de le t ed because they a r e so f a r ou t s ide the knowledge of t h e au thor s and o t h e r s who worked on t h e a t o l l , and o u t s i d e t h e ob jec t ives of t h e POBSP, a s t o make t h e i r d iscuss ion mean- i n g l e s s . References to a l l p e r t i n e n t papers a r e included where they a r e known, but t h e r e i s implied no pre tense t h a t the r e fe rences included comprise a comprehensive bibl iography. Emphasis of t h e POBSP was on a n a l y s i s of t h e n a t u r a l h i s t o r y of t h e t e r r e s t r i a l v e r t e b r a t e s and t h e t e r r e s t r i a l vascular p l a n t s , wi th by f a r t h e g r e a t e s t emphasis on t h e b i r d s . I n t h e fol lowing treatment t h e only groups l i s t e d i n d e t a i l bes ides these two c a t e g o r i e s a r e t h e inshore f i s h e s and i n s e c t s . P l a n t s The marine and t e r r e s t r i a l p l a n t s of Johnston A t o l l a r e wel l known. Both have been heavi ly d is turbed by man. Only one marine a l g a l spec ie s was known from Johnston A t o l l p r i o r t o 1965 (Moul, 1964). A s p a r t of a s tudy of the e f f e c t s of dredging on Johns ton ' s marine environment, 67 spec ies of benthic marine a lgae were co l l ec t ed by t h e Hawaii I n s t i t u t e of Marine Biology, Univers i ty of Hawaii, 17-22 August 1965 and 17-21 December 1965 (Buggeln and Tsuda, 1966). Co l l ec t ions were made i n 1 4 h a b i t a t a r e a s (Fig. 29). Additional c o l l e c t i o n s from 16 o ther h a b i t a t a r e a s were made 14-24 June 1966 by t h e Department of Radiat ion Biology, Univers i ty of Washington; from t h e s e c o l l e c t i o n s 26 more spec ie s of a lgae were added t o t h e known spec ie s l ist (Buggeln and Tsuda, 1969). The d i s t r i b u t i o n of t h e 93 spec ie s of benth ic marine a lgae known from Johnston A t o l l (Table 2) shows t h a t 12 spec ie s were found only from t h e marginal r e e f , while 33 spec ie s were found only i n t h e lagoon waters . Figure 29. Algae c o l l e c t i o n s t a t i o n s , Johnston Ato l l , 1965-1966 (Buggeln and Tsuda, 1969). Of t h e s e 33 lagoon spec ie s , I1 were found only i n open water , 11 occurred only i n t h e inshore Johnston Is land a rea , and 2 were taken i n t h e inshore Sand Is land a r e a . Buggeln and Tsuda (1966) suggest a v e r t i c a l d i s t r i b u t i o n of t h e Johnston algae--especial ly Chlorophyta and Rhodophyta--in t h e sub- l i t t o r a l zone, such t h a t a s l i g h t i n t e n s i t y decreases with depth , t h e number of a l g a l spec ie s a l s o dec l ines . These au thor s , a s wel l a s Brock, Henkelem, and Helfnich (1966), found a c o r r e l a t i o n between in- creased s i l t i n dredge-affected a r e a s and decreased number of a l g a e spec ie s . The s i l t caused a reduct ion i n l i g h t i n t e n s i t y a t a l l depths ; l ack of l i g h t reduced photosynthesis and thus eliminated p l a n t s . They a l s o found t h a t i n t h e newly dredged and widened s h i p channel (a reas 10 and l l ) , t h e new su r face had been invaded by sparse Cyanophyta and Rhodophyta spec ies . I n some of t h e dredged a reas r a t h e r thiclc a l g a l mats developed over t h e whole bottom. The blue-green a lga Lyngbya majescuza was t h e dominant spec ie s ; o the r s included Sehizothrix caZcieoZa and Phormidiwn submembranacewn. Table 2 . D i s t r ibu t ion* of benthic marine a l g a e a t Johnston A t o l l Lagoon Divis ion Marginal Open Inshore Inshore Species Reef Water Johnston Sand Cyanophyta Anacystis dimidiata EntophysaZis deusta Schizothrix caZcicoZa HydrocoZewn Zyngbyacewn Microcoteus chthonopZastes MicrocoZeus tenerrimus Microco Zeus vaginatus Lyngbia aes tuar i i Lyngbia confervoides Lyngbia Zutea Lyngbya ma juscuZa SpiruZina tenerrima Symptoca atZantica Oscit iatoria n igrov i r id i s Phormidiwn submembranacewn Hormothamnion enteromorphoides CaZothrix crustacea CaZothriz scopuZoman I sac t i s pZana Chlorophyta PaZmogZoea protuberans Enteromorpha k y l i n i i Cladophora crystaZZina CZadophoropsis sp. VaZonia ventricosa Dictyosphaeria versZuysii Broodlea composita Microdictyon setcheZZianwn Dervesia marina Derbesia sp. Cau Zerpa ambigua CauZerpa racemosa macrophysa CauZe~pa urv i t t iana Bryopsis pennata ~seudochtorodesmis parva Codium arabicwn Codizun sp. HaZimeda discoidea HaZimeda tuna AcetabuZaria clavata Acetabularia mobii AcetabuZaria tsengiana AcetabuZaria sp . Table 2. (continued) Divis ion Species Chrysophyta Ostreobiwn reineckei Phaeophyta Ectocarpus breviar t iculatus Ectocarpus indieus Ectocarpus irreguzaris Ectocaxpus sp . Sphacetaria furcigera SphaceZaria novaehoZZandiae SphaceZaria tr ibuloides Dictyota sp. PocockieZZa variegata Rhodophyta Asterocystis ornata Goniotrichum aZs id i i Erythrotrichia sp . GeZidiwn crinale pe rpus i l tm GeZidiwn pusiZZm pusiZZwn Wurdemania sp . ~ a n i a capiltacea Jania decussato-dichotoma Amphiroa sp. Hypnea esperi i~men tar ia hakodatensis Champia parvuZa Antithamnion a n t i l Z a m CaZZithamnion marshaZZensis ~allitharmzion sp . Centroceras apicuZatum Centroceras cZavuZatm Crouania minutissima Ceramiwn a f f i n e Ceramim fimbriatwn Ceramiwn graciZZimwn byssoidem Ceramiwn huysmansii Ceromiwn maryae Ceramiwn vagabunde Ceramiwn zacae Ceramim sp. Crouania minutissima Gr i f f i t h s ia metcaZfi i Gr i f f i t h s ia oval is Lagoon Marginal Open Inshore Inshore Reef Water Johnston Sand Table 2. (continued) Lagoon Divis ion Marginal Open Inshore Inshore Species Reef Water Johnston Sand Rhodophyta ( can t . ) G r i f f i t h s i a t e n u i s G r i f f i t h s i a sp. Dasya adherens Dasya s inicoZa Dasya sp . Taenioma macrounvn CaZogZossa Zepr i eu r i i Neterosiphonia wurdemanii Zaxa Herposiphonia sPP Polysiphonia sPP Laurencia sp . Chrondria repens "Figures i n d i c a t e t o t a l number of c o l l e c t i o n s t a t i o n s from which samples were taken. See Figure 29 f o r c o l l e c t i o n s t a t i o n l o c a l i t i e s ; Marginal Reef l o c a l i t i e s : 1 ,2,4,12,27,28,29; Lagoon Open Water: 3,5,6,8,9,10,11,17; Lagoon Inshore Johnston: 13 ,14 ,15 ,16 ,18 ,19 ,20 ,21 ,22 ,23 ,24 ; Lagoon Inshore Sand: 7,25,26,30. Vascular P l a n t s Table 3 l i s t s t h e 51 f a m i l i e s , 109 genera, and 127 spec ie s of vascu- l a r p l a n t s t h a t have been i d e n t i f i e d from t h e four i s l a n d s a t Johnston toll. This number i s remarkable, f o r i n 1859 Brooke (ms.) noted only two p l a n t s and i n 1923 t h e TANAGER-WHIPPOORWILL expedit ion found only t h r e e spec ie s of vascular p l a n t s (Chris tophersen, 1931). By 1946, 27 spec ie s were recorded from Johnston I s l and (Fosberg, 1949), and by 1954, 43 spec ie s occurred t h e r e (Newhouse, 1955). By 1963, 77 spec ie s were known from both Johnston and Sand I s l a n d s (POBSP, 1964). The t h r e e p l an t spec ie s recorded by 1923 probably reached t h e a t o l l through n a t u r a l means e i t h e r by water c u r r e n t s , a i r , o r b i r d s . A few spec ie s found s i n c e poss ib ly a l s o a r r i v e d v i a these same ways, but t h e ma jo r i ty of t h e remaining 124 spec ie s has been man-made i n t r o - duc t ions . Some of these in t roduc t ions were i n t e n t i o n a l , o the r s came a s stowaways or adventives. Or ig ina l Flora L t . John M. Brooke (ms.) no ted t h e fol lowing i n h i s j ou rna l f o r 16 March 1859: h here i s a downy creeping p l a n t bearing a yellow f lower, and g r a s s , t h e s e a r e t h e only r e p r e s e n t a t i v e s of the vegetable kingdom." Table 3 . Vascular p l a n t s known from Johnston A t o l l I s l ands Family Sand Species John- Sand Man- Common Name Akau Hikina s ton Orig. made Polypodiaceae Ferns Polypodiwn scolopendria Nephrolepsis sp . Araucar iaceae Araucaria heterophyl la Norfolk I s l and pine Pandancaceae Pandanus tec tor ius? Screw-pine, ha la Graminea Grasses Cenchrus echinatus Sandbur ChZoris barbata Fingergrass Cynodon dactylon Bermuda g r a s s Dactylocteniwn aegyptium Crowfoot g r a s s Digitaria sanguinalis Crabgrass EchinochZoa erus-gaZZi Barnyard g r a s s Eleusine indica Goose g r a s s Eragrostis t ene t ta ( i n c l . amabil is) Lovegrass Leptums repens Bunch g r a s s A = Adventive; N = Native; P = Planted; S = Seed only Table 3. (continued) I s l ands Family Sand spec ie s John- Sand Man- Common Name Akau Hikina s t o n Orig. made Graminea (cont .) Paspalwn dilatatum Dal la s g r a s s S a c c h m off icinarwn Sugarcane Setaria v e r t i c i l l a t a B r i s t l e g r a s s Sporobolus v irginicus Dropseed Zea mays Corn Cyperaceae Sedges Cyperus rotundus FimbristyZis cymosa? Palmae Palms 'Z era Cocos nuc ' f Coconut palm Araceae Anthuriwn andraeanwn An thur ium L i i i a c e a e AZZiwn fistuZoswn Welsh onion AZZiwn sp . Chives Aloe sp . Aloe Cordyline fruticosa Cordyline Sansevieria t r i f a c i a t a Bowstring Hemp Table 3 . (continued) I s l a n d s Family Sand Species John- Sand Man- Common Name Akau Hikina s t o n Orig. made Amaryllidaceae Cr inm a s i a t i c m Crinwn sp . HymenocaZZis ZittoraZis P Spider l i l y Bromeliaceae Anams comosus Zingiberaceae AZpina sp. Ginger Musaceae He Ziconia hwniZis S t reZi t z ia r eg ime Bird of Paradise Orchidaceae Orchids Epidendrwn sp . Vanda sp. Casuar inaceae Casuarina equiset i foz ia Ironwood Moraceae Ficus microcarpa Banyan U r t i caceae PiZea microphyZZa A r t i l l e r y p l an t Polygonaceae CoccoZoba w i f e r a Sea-grape Chenopodiaceae Chenopodim muraze Goosefoot, Pigweed Amaranthaceae Pigweeds Amaranthus dubius Table 3 . (continued) I s l ands Familv Sand Species John- Sand Man- . made Amaranthaceae (cont . ) A . spinosus A. v i r id i s Nyctaginaceae Boerhavia sp. BougainviZzea s p . Aizoaceae Tetragonia tetragonioides New Zealand Spinach Por tu lacaceae Portulaca oleracea Purs l ane Caryophyllaceae Spergutaria marina Lauraceae Persea americana Avocado Cruci ferae LobuZaria maritima Sweet Alyssum Rosaceae Eriobotrya japonica Loqua t Leguminosae Acacia farnesiana Sweet Acacia CrotaZaria incana Rat t lebox Phaseolrus sp . Bean Table 3 . (continued) I s l a n d s Family Sand Species John- Sand Man- Common Name Akau Hikina s ton Orig. made Leguminosae (cont .) Pism sativwn Pea Mucuna sp. PitheceZZobium dulce Manila Tamarind Prosopis paZZida Algarobe, Kiawe Vigna marina Beach pea Zygophyllaceae l'ribulus cistoides Puncture Vine Ruthaceae Citrus aurantifoZia Lime Citrus sinensis Orange Euphorbiaceae AZeurites moZuccana Candlenut, Kulcui Codiaewn variegatwn var pictwn Cro ton Euphorbia atoto? Spurge E. prostrata Spurge E. prob. heterophyZZa Spurge Table 3 . (continued) I s l a n d s Familv Sand Species John- Sand Man- Common name Akau Hikina s t o n Orig. made Euphorbiaceae (cont . ) E. glomerifera Spurge E. h i r ta Spurge E. pulcherrima P o i n s e t t i a PediZanthus tithymeloides Sl ipper flower Ricinus cormnunis Castor bean Anacardiaceae Mangifera indica Mango Schinus t ereb in th i fo l ius Christmas ber ry t r e e T i l i a c e a e p i m f e t t a procwnbens Malvaceae Hibiscus t i t i aceus Hau Hibiscus sp. Thespesia populnea Milo t r e e , P o r t i a t r e e Sida sp. S t e rcu l i aceae Valtheria indica G u t t i f e r a e CalophyZZm inophy l lm Fa l se IZamani Table 3 . (continued) I s l ands Familv Sand Species John- Sand Man- Common Name Akau Hikina s t o n Orig. made Combretaceae Termimlia catappa Indian almond, Kamani Myrtaceae Eucalyptus sp. Ara l iaceae Brassaia actinophylla Octopus t r e e Polyscias gu i l f oy l e i Wild co f fee Caricaceae Carica papaya Papaya Plumbaginaceae Plwnbago auriculata Plumbago, Leadwort Apocynaceae Catharanthus roseus Madagascar Periwinkle Ner im oleander Oleander Plmer ia acumimta Frangipani Plwneria rubra Frangipani Thevetia peruviana v a r . aurantiaca T . pemviana (=nerei fo l ia) Yellow Oleander Convolvulaceae Ipomoea indica Table 3 . (continued) I s l ands Family Sand Species John- Sand Man- Common Name Akau Hikina s ton Orig. made Convolvulaceae (cont.) I. pes-caprae Beach Morning Glory I. macrantha ? Merremia tuberosa Wood Rose Hydrophyllaceae Nama sandwicensis Boraginaceae Cordia sebestena Kou, Geiger-Tree Heliotropiwn eurassavicwn Tournefortia argentea Tree Hel io t rope Verbenaceae Staehytarpheta jamaicensis A Vi tex ovata P P Solanaceae C a p s i m frutescens P Papper SoZanum Zycopersicwn P ? P ? P Tomato SoZanwfl me Zogena Eggplant Bignoniaceae Tabebuia pentopkylta Wcst Indian Boxwood Rubiaceae Gardenia sp. Coprosma sp. Table 3. (continued) Cucurbitaceae CitruZZus Zanatus var. vuZgaris Watermelon Cucwnis melo Muslanelon Goodeniaceae Scaevola taccada Compositae Bidens pilosa Burmar igold Conyza bonariensis Helianthus annuus Sunflower PZuchea indica PZuchea capo Zinensis PZuchea x Fosbergii Sonchus sp. (oZeraceus x asper) ? Sow-thistle Tagetes sP. Marigold Vernonia cinerea Ironweed Zinnia etegans Zinnia "The nea res t approach t o t h e p l an t I could f ind i n my elementary Botany i s t h e por tu laca , t h e same p l a n t grows on Laysan. I gave a specimen t o D r . Hilebrand a t Honolulu." Brooke (Zoc. c i t . ) a l s o mentioned t h a t Capt. A.D. P ipe r , i n charge of t h e i s l a n d , had " . . .p lan ted pota toes and pumpkins, but they withered away." Brooke gave Piper seeds of t h e following: watermelons, muskmelons, squash, egg p l a n t , pepper, asparagus, s o r r e l , l e t t u c e , and leek . I f Piper planted these , t h e i r u l t i m a t e f a t e was the same a s t h a t of t h e pota toes and pumpkins, f o r none survived u n t i l t h e next known d e s c r i p t i o n of t h e a t o l l ' s vege ta t ion , made 64 years l a t e r . Members of t h e TANAGER Expedit ion found only t h r e e spec ie s of vas- cu la r p l a n t s growing on Johnston A t o l l i n 1923: Lepturus re e n s , yribuZus c i s t o i d e s , and Boerhavia sp. [u sua l ly r e f e r r e d t o a s diffusa? (Christo- phersen, 1931: 4 ) . The g r a s s Brooke found growing i n 1859 almost c e r t a i n l y was Lep-hrus , and t h e "downy creeping p lan t bear ing a yellow flower" was most l i k e l y T ~ i b u z u s . Brooke's t e n t a t i v e i d e n t i f i c a t i o n of it a s a Por tu laca seems u n l i k e l y i n view of t h e laclc of downiness of Por tu laca and of i t s absence from t h e a t o l l i n 1923. It i s cu r ious , however, t h a t Brooke d i d not men- t i o n t h e armed f r u i t s , i f indeed t h e p l an t was TribuZus. Although these f r u i t s a r e not so conscicuous i n March a s l a t e r i n t h e season, old f r u i t s remain sharp enough t o p e n e t r a t e t h i n shoes f o r many months, and c e r t a i n l y should have been present and no t i ceab le t o Brooke. I f Boerhavia were present i n 1859, i t apparent ly was not abundant enough f o r Brooke t o n o t i c e i t r e a d i l y . While i t seems u n l i k e l y t h a t such a p l a n t could be missed i f i t were present i n anything near t h e abundance i t was found i n 1923, i t seems equal ly u n l i k e l y t h a t such an e a s i l y d i s t r i b u t e d spec ies would have t o await t h e he lp of man t o reach Johnston A t o l l . The ambiguity of t h i s s i t u a t i o n leaves u s i n doubt a s t o whether t h e o r i g i n a l vege ta t ion of t h e a t o l l cons is ted of two o r t h r e e spec ie s . I n e i t h e r case , i t i s , a s Fosberg (1949) pointed ou t , one of t h e smal les t f l o r a s known. A l l t h r e e p l a n t s i n quest ion have propagules t h a t could be t ranspor ted e a s i l y by b i r d s by s t i c k i n g t o o r i n t h e plumage (Boerhavia and Lepturus) or by s t i c k i n g i n t o t h e f e e t (Tr ibulus) . It is not su rp r i s ing t h a t t h e c u l t i v a t e d p l a n t s Brooke and Piper introduced t o t h e a t o l l died o u t , but i t i s remarkable t h a t none of t h e common weedy spec ie s from other p a r t s of t h e world became es t ab l i shed from s h i p ' s cargoes. It would be most i n t e r e s t i n g t o know i f any of t h e s e were indeed introduced p r i o r t o 1923, and i f so , how long they per- s i s t e d . Perhaps t h i s s i t u a t i o n i s evidence t h a t many common weeds r e q u i r e continued d is turbance by man t o a s s u r e t h e i r pe r s i s t ence . Recent Vegetat ion I n t h e yea r s s ince 1923, t h e a t o l l ' s f l o r a has been enriched by numerous in t roduc t ions , both i n t e n t i o n a l and otherwise. Wetmore (ms.b) planted e i g h t "c l ips" of Hau (Hibiscus t i t i a c e u s ) 18 Ju ly 1923. These may not have survived f o r t h e spec ies was not included on t h e next l i s t of t h e f l o r a , compiled by Bryan (ms.b) i n 1944. This l i s t showed 29 spec ie s of n a t i v e and introduced p l a n t s . The next published l i s t was t h a t of F.R. Fosberg (1949) based on c o l l e c t i o n s made 1 November 1946 by h i s b ro the r , K.P. Fosberg. This showed 27 spec ie s , inc luding e i g h t not l i s t e d by Bryan i n 1944, br inging t h e t o t a l known f l o r a t o about 35. Doty and Newhouse (ms.) summarized previous f ind ings , inc luding a d d i t i o n a l d a t a from Fosberg, together wi th r e s u l t s of a study of t h e vege ta t ion fos t e red by L t . Col. Jack Bently, Base Commander, i n 1953 i n which 44 a d d i t i o n a l spec ie s were found. Of t h e s e 44, 20 were grown only i n yards under ca re of r e s i d e n t s . About 51 spec ie s apparent ly grew untended then, wi th an a d d i t i o n a l 18 tended, f o r a t o t a l f l o r a of 69 spec ie s . POBSP s t u d i e s , p r i n c i p a l l y by A. Binion Amerson, Jr . , Charles H. Lamoureux, and P h i l i p C. Shel ton, added 48 spec ie s t o t h e Johnston A t o l l f l o r a . Included were t h e f i r s t c o l l e c t i o n s from t h e two new i s l a n d s , Akau and Hikina. I s land Accounts Appendix Tables 2 through 6 p resen t annotated l i s t s of a l l vascular p l an t spec ie s known t o have occurred on each i s l and a t Johnston A t o l l , with t h e exception of i n t roduc t ions t h a t have f a i l e d , such a s some of t h e c u l t i v a t e d spec ie s introduced by Brooke and P ipe r , and c e r t a i n l y many o the r s . Land c l e a r i n g and dredge f i l l have increased t h e s i z e of t h e two o r i g i n a l i s l a n d s and have made two new i s l a n d s , t hus b e t t e r i n g t h e op- po r tun i ty f o r more p l a n t spec ies . Disturbed s o i l together wi th freedom from competi t ion by an e s t ab l i shed f l o r a have provided condi t ions s u i t a b l e f o r many kinds of p l a n t s . But some p l a n t s have not been a b l e t o surv ive t h e poor s o i l and c l imate condi t ions of Johnston. Thus, many of t h e ornamental spec ie s i n t e n t i o n a l l y introduced by man would not surv ive i f not f r equen t ly cared f o r by man. Because of human d is turbance , t h e p l a n t s occurr ing on t h e four i s l a n d s a r e d i f f e r e n t i n spec ie s composition. Akau Is land: There a r e 38 spec ie s of vascular p l a n t s known from Akau I s l and . This i s l and has a much l a r g e r f l o r a than Ilikina I s l a n d , both of which were b u i l t a t t h e same t ime, p a r t l y because of i t s c l o s e r pos i t i on t o Johnston and Sand I s l ands , but more important ly because of more i n t e r e s t i n p l a n t s by workers on Akau than on Hikina. Most of ~ k a u ' s f l o r a c o n s i s t s of spec ie s t ransplanted from Johnston I s l a n d . S ix spec ie s recorded from Akau, however, a r e not lcnown from t h e other t h r e e i s l ands . This man-made i s l and was completed i n 1964; by September 1967, 3 1 spec ies were growing t h e r e . Sixteen of these 3 1 were obvious in t roduc t ions ; t h e remaining 15 were considered t o be advent ive and not i n t e n t i o n a l l y planted. Only a few of each of t h e introduced spec ie s e x i s t e d , but a t l e a s t f i v e of t h e advent ive spec ies were common. FimbristyZis sp. grew over most of t h e i s l a n d and was t h e most dominant spec ies . Spergutaris marina was widespread, and small p l a n t s of Sesuv im portuZacastmun were s c a t t e r e d about. EZeusine indica was f a i r l y abundant i n a few small a r e a s . Two pa tches of C'ynodon dactyzon, one about 30 f e e t i n diameter , grew i n a s l i g h t depress ion on t h e nor th-cent ra l po r t ion of t h e i s l and (POBSP, 1967b). Similar p l a n t d i s t r i b u t i o n ex i s t ed i n November 1973. Hikina Is land: Only 14 spec ie s of vascular p l a n t s have been recorded from Hikina I s l and (Table 3 ) . A l l a r e known from a t l e a s t one of t h e o t h e r t h r e e i s l a n d s ; t h r e e a r e known from seed only. The i s l and was completed i n 1964 and by September 1967 f i v e spec ie s of growing p l a n t s and seeds of t h r e e spec ie s were recorded. Two of t h e f i v e growing s p e c i e s were represented by one specimen each; both were obvious in t roduc t ions . Fimbristyt is sp . was t h e dominant p l a n t and oc- curred s c a t t e r e d on almost t h e e n t i r e i s l a n d . Sesuviwn por tuZacas tm was t h e second most abundant spec ie s and grew i n clumps, t h e l a r g e s t of which was 6 by 9 f e e t . SperguZaria marina, t h e t h i r d ranking spec ie s , was widely s c a t t e r e d over t h e i s l a n d , but most p l a n t s appeared t o be dead. The t h r e e seeds were a l l on t h e beach (POBSP, 1967b). The i s l and was r e v i s i t e d i n February 1969 and two a d d i t i o n a l spec ie s of g r a s s were recorded. The f l o r a looked about a s i t d id i n September 1967, except t h a t t h e FimbristyZis was more evenly spread, although l i t t l e changed i n d e n s i t y (POBSP, 1969). The f l o r a was t h e same i n November 1973, except f o r a l a r g e Pluchea bush growing i n t h e nor th-cent ra l por t ion . Johnston Is land: I n 1923, a s mentioned e a r l i e r , only t h r e e p l an t spec ie s were known (Chris tophersen, 1931). Wetmore's 1923 photographs show Lepturus repens a s t h e dominant spec ies . U.S. Navy a e r i a l photographs taken i n 1935 and 1939 ( see Figs . 3 and 5) r e v e a l vege ta t ion growing over t h e e n t i r e i s l a n d ; another taken i n May 1941 shows o r i g i n a l vege ta t ion everywhere except around t h e bui ld ings on t h e no r theas t corner and i n an a r e a no r th t o south a c r o s s t h e cen te r . By 1942, another a e r i a l photograph ( see Fig. 6) shows no vege ta t ion a t a l l and numerous bu i ld ings . Twenty-seven p l a n t spec ie s were recorded i n 1946; these cons is ted mainly of obvious in t roduc t ions and a c c i d e n t a l weeds. No o r i g i n a l vegeta- t i o n remained; t h e whole i s l and was occupied by runways and bu i ld ings with d is turbed ground i n t h e open p laces and along pa ths and roads ides (Fosberg, 1949). I n January 1954, Newhouse (1955) found 43 p l a n t spec ies ; 20 were not under c u l t i v a t i o n and 23 were under c u l t i v a t i o n i n dependents' homes and gardens. Three p l an t spec ie s recorded i n 1949 were not observed i n 1954. By 1967, 111 plan t spec ie s had been recorded from Johnston Is land (Table 3 ) . Of these 111, 3 were n a t i v e , 61 were p lanted , 44 were adventive, and 3 of ques t ionable s t a t u s . I n add i t ion , 56 of t h e 111 were not known from t h e o ther t h r e e i s l a n d s . Continued d is turbance on Johnston I s l and i n 1967 prevented any meaningful development of vege ta t ion except i n a few s c a t t e r e d l o c a t i o n s near t h e runway. Pluchea c a r o l i n e n s i s , which a t t imes has been kept trimmed, had developed conspicuous s t ands on t h e south s i d e of t h e runway, e s p e c i a l l y no r theas t of t h e Weather Bureau bui ld ing; nes t ing Red-tailed Tropicbi rds were e s p e c i a l l y a t t r a c t e d t o t h e s e s tands . Only one o ther spec ie s , Cenchrus echina tus o r sandbur, was considered t o be f a i r l y abundant on open d is turbed a reas . Other spec ies ranged i n number from ind iv idua l p l a n t s t o widely s c a t t e r e d , but not abundant p l a n t s (POBSP, 1967b). I n November 1968, most of t h e Casuarina e q u i s e t i f o l i a , or ironwood t r e e s , were removed from a top t h e underground h o s p i t a l , t hus des t roying some of t h e prime White Tern roos t ing and nes t ing h a b i t a t (POBSP, 1968). By November 1973, Casuarina t r e e s near t h e t e n n i s cour t s were supporting n e s t s of both White Terns and Black Noddies. Sand Is land: A t o t a l of 54 spec ie s of vascular p l a n t s has been recorded from Sand Is land (Table 3 ) : 3 were n a t i v e spec ie s , 23 were p l an ted , 26 were adventive, and 2 occur only a s seeds. Nine spec ie s found he re a r e not known from t h e o ther t h r e e i s l ands . Or ig ina l : Three species--Lepturus repens , Boerhavia repens , and Tr ibulus cistoides--were recorded i n 1923 (Chris tophersen, 1931). Ground-level photographs taken i n 1923 by Wetmore r evea l L. repens t o be t h e dominant spec ies . U.S. Navy a e r i a l photographs taken during t h e mid- 1930's ( see F ig . 3) show t h e i s l a n d completely covered by vege ta t ion . The a r r i v a l of a permanent m i l i t a r y s t a t i o n i n 1939 (see Fig . 8) s ignaled d e s t r u c t i o n of t h e o r i g i n a l f l o r a ; by March 1940 (see Fig . 9) vege ta t ion remained only on t h e no r th peninsula . POBSP personnel recorded 11 spec ie s of p l a n t s h e r e i n 1963. Some 80 percent , or approximately 400,000 square f e e t , of t h e o r i g i n a l po r t ion , was covered by vegeta t ion . The f i v e most dominant spec ie s (Fig. 30) were, i n order of importance, Lepturus repens , Tr ibulus c i s t o i d e s , Sesuvium por tu l acas t run , Boerhavia r epens , and Amaranthus v i r i d i s . The f i r s t t h r e e spec ie s covered 84 percent of t h e vegetated a rea (Leptums 50 percent , !l'ribulus 30 percent , and Sesuviwn 4 pe rcen t ) . The e igh t o ther spec ie s f i l l e d t h e remaining 16 percent and were pr imar i ly s c a t t e r e d over bare s o i l and rock (POBSP, 1964). Seasonal c l ima t i c cond i t ions and human d is turbance o f t e n a f f e c t t h e i s l a n d s ' f l o r a . For example, i n e a r l y February 1967 t h e vege ta t ion appeared d r i e r than i t had i n October 1966, al though s e v e r a l spec ie s had spread not iceably during t h e winter . A t l e a s t two spec ie s , Boerhavia repens and TribuZus c i s t o i d e s , were reduced i n numbers. Heavy r a i n s i n February and March brought t h e growth up t o t h e October 1966 l e v e l ; t h e r e was only a s l i g h t dec l ine i n greenness by e a r l y May. By l a t e August and September, when t h e f l o r a was usua l ly a t i t s lowest growth, t h e vegeta t ion appeared a t l e a s t a s vigorous and green a s i n May, and much more so than a t t h e same time i n 1966. By 1967, 25 p l an t spec ie s were known from t h e o r i g i n a l po r t ion of Sand I s l and (Table 3 ) . Of t h e s e 25, 3 were na t ive , 2 were p lanted , 18 were adventive, and 2 occurred a s seeds. P l a n t d i s t r i b u t i o n a s of l a t e 1967 (Fig. 31) and l a t e 1968 was s i m i l a r t o t h a t i n l a t e 1964 except t h a t Boerhavia was more widespread on t h e e a s t e r n ha l f (POBSP, 196713, 1968). Sparse p l a n t s were observed i n November 1973, most l i k e l y r e s u l t i n g from low spr ing r a i n f a l l coupled wi th l a r g e numbers of Sooty Terns. Man-made: The man-made por t ion was s t a r t e d i n l a t e 1939 and by May 1941 was nea r ly completed. A U.S. Navy a e r i a l photograph taken i n February 1942 from a he ight of 600 f e e t r e v e a l s no vegeta t ion . POBSP personnel recorded 19 spec ie s of p l a n t s he re i n 1963; 9 of t hese 19 were not growing on t h e o r i g i n a l p o r t i o n (POBSP, 1964). By 1967, 50 p l an t spec ie s had been recorded (Table 3 ) . Of t h e s e 50, 23 were obviously introduced, and 27 were probably adventive. I n a d d i t i o n , 29 of t h e 50 spec ie s were not growing on t h e o r i g i n a l po r t ion , and seven were not growing on t h e o ther t h r e e i s l a n d s i n t h e a t o l l . I n 1967, pioneer advent ive spec ie s inc luding Fimbris tyZis , Conyza, Sonchus, Cenchrms, and PZuchea were inc reas ing on t h e newest c o r a l , dredged i n 1964. Other spec ie s , inc luding Cynodon, Sesuviwn, and Euphorbia h i r t a , were rep lac ing t h e above f i r s t four on t h e o lder dredged por t ion . ScaevoZa continued t o grow wel l around t h e bui ld ings i n 1968 and 1969, t hus providing nes t ing h a b i t a t f o r Red-tailed Tropicbi rds (POBSP, 1967b, 1968, and 1969). A s imi l a r d i s t r i b u t i o n was found i n November 1973. Inve r t eb ra t e s The i n v e r t e b r a t e fauna of Johnston A t o l l i s not well-known and while s c a t t e r e d c o l l e c t i o n s have been made, no extens ive systematic sampling programs have been conducted. Most of t h e published l i s t s appear t o be s p o t t y and t h e ecologica l a spec t s of t h e zoogeography have been l a r g e l y neglected. Published r e p o r t s and museum c o l l e c t i o n s cen te r around t h e macro- i n v e r t e b r a t e s of t h e major phyla Cnidaria , Mollusca, Annelida, Arthro- poda, and Echinodermata. Of these phyla, even t h e corals--the most conspicuous group of t h e a t o l l marine fauna--are not well s tud ied . There a r e l i t t l e or no da ta a v a i l a b l e on other groups such a s t h e sponges orif if era), t h e acoelomate b i l a t e r i a ( e .g . , p la tyhelminthes) , t h e pseudocoelomates ( e .g . , Aschelminthes), t h e minor coelomate proto- stomes (e. g. , Pr iapu l ida , Sipunculida, Echiurida) , the lophophorate coelomates (e .g. , Phoronida, Ectoprocta, Brachiopoda), and t h e minor deuterstome phyla (e .g. , Pogonophora, Hemichorda). The i n v e r t e b r a t e fauna ( e s p e c i a l l y t h e Mollusca) known from Johnston A t o l l , however, i n d i c a t e s t h a t Johnston may se rve a s a unique f i l t e r br idge between t h e south-cent ra l (Polynesian) and western (Micronesian) P a c i f i c fauna and t h e Hawaiian fauna. Lepturur pepens o Tribulus c i s t o i d e s . partulacartrurn 0 rn sp. N * Atnaranthus viridis I 0 100 200 - Feet Figure 30. Distribution of the five most important plant species on the original portion of Sand Island, Johnston Atoll, July-August 1963. ... ~ e p t u r u s repens - - Scaveola taccada o TrihuluI c i s t o i d e s @ Ipomoea indica . p~"t"laCaPtT"m 0 vigna mavim 0 Boerhavia s p . m Sonchur sp. * Amavanthus v i r i d i s Q caro l inens i s . Ipamoea pes-caprae @ Tournefortia argentea N ii Portulaca aleracea r Cynodon dactylon r 0 100 200 - Feet Figure 31. Distribution of dominant plant species on the original portion of Sand Island, Johnston Atoll, May 1967. Cnidaria (Coelenterata) Eighteen spec ie s i n 11 genera of Cnidaria (hydras, j e l l y f i s h , sea anemones, and c o r a l s ) a r e known from Johnston A t o l l (Table 4). The d i s t r i b u t i o n and abundance of t h e seven genera of c o r a l reported by Brock, e t aZ. (1965, 1966) a r e presented i n Table 5 . Col lec t ion s t a - t i o n s a r e shown i n F igure 32. Two genera a r e q u i t e r e s t r i c t e d , occurr ing only i n a r e a s 1 and 2 near t h e marginal r e e f . The o the r f i v e genera a r e d i s t r i b u t e d widely throughout t h e lagoon. Dredging opera t ions i n 1964 destroyed over 1,100 a c r e s of r e e f ; dredging i t s e l f destroyed 700 a c r e s of l i v i n g c o r a l while newly deposi ted 11 c o r a l aggregate" destroyed more than 400 ac res . I n a d d i t i o n , over 7,000 a c r e s of r ee f and lagoon were more or l e s s s e r i o u s l y a f f ec t ed by s i l t y water. The reduct ion i n t h e percentage of l i v i n g c o r a l i n these s i l t y water a r e a s var ied from none t o 40 percent , w i th 10 percent being roughly an average f i g u r e . A p a r a l l e l reduct ion i n t h e number of assoc ia ted i n v e r t e b r a t e spec ie s and f i s h spec ie s a l s o occurred. Figure 32. Johnston A t o l l showing i n v e r t e b r a t e and f i s h c o l l e c t i o n s t a t i o n s , dredged a r e a s , and t h e ex ten t of s i l t laden water (Brock, e t dl., 1966). T a b l e 4. C n i d a r i a ( C o e l e n t e r a t a ) from Johns ton A t o l l * Class Wells Brock P r e s e n t Family 1934 et az. Paper S p e c i e s 1965 Hydrozoa M i l l e p o r i d a e MiZZepora tenera MiZZepora s p . S t y l a s t e r i n i d a e Distichopora sp . Stylaster s p . Anthozoa P o c i l l o p o r i d a e PociZlopora damicornis PociZZopora eydomi PociZZopora meandrim Acropor idae Acropora humiZis Acropora hyacinthus Acropora retusa Acropora twnida Montipora verrucosa Montipora s p . A g a r i c i i d a e Leptastrea s p . Pavona variens Pavona s p . F u n g i i d a e mngia scutaria P o r i t i d a e Portites Zutea I s o p h e l i i d a e Telmatactis decora *Taxonomic o r d e r f o l l o w s Bayer, et aZ. (1956) . T a b l e 5 . D i s t r i b u t i o n and abundance o f c o r a l s a t ~ o h n s ' t o n A t o l l , 1964-1965" 1 (1964) X X X X X X X Mound t o p s 7 0 t o 100% Lower s i d e s 40 t o 50% 2 (1964) X X X X X X X Ridge t o p s 99% Channel f l o o r 1% 4 (1964) X X X X X 20% o r less 4 (1965) X X X X X 1 0 t o 20% 5 (1964) X X X X X 90 t o 95% 5 (1965) X X X X X 50 t o 75% 6 (1964) X X X X X X 50 t o 75% 6 (1965) X X X X X X 50 t o 70% 7 (1964) X X X X X X 2 0% 7 (1965) X X X X X X 15% X X X X X 20 t o 30% X X X X X 1 5 t o 20% 9 (1964) X X X X 50 t o 60% 1 0 Reef"" X 1 0 C l i f f 1 0 Bottom 11 Reef X X X X X 60 t o 70% 11 C l i f f 0% 11 Bottom X C O . 1% 1 2 Reef 1 2 C l i f f 1 2 Bottom 1 3 Reef X X X X X 1 0 t o 15% 1 3 C l i f f 0% 1 3 Bottom 0% Number o f X's 1 5 1 6 8 1 1 8 1 9 1 6 2 10% *Adapted f rom Brock , e t al. (1965, 1 9 6 6 ) . **Areas 1 0 t h r o u g h 1 3 , 1965 o n l y . Mollusca (by Harald k . Rehder) The 58 spec ie s l i s t e d i n Table 6 comprise only those mollusk spec ie s found i n t h e c o l l e c t i o n of t h e National Museum of Natural His tory and by no means r ep resen t t h e complete fauna of t h i s a t o l l . A thorough survey of t h e lagoon and a search of t h e reef and shores of both Sand and Johnston I s l a n d s f o r t h e smaller spec ie s would inc rease t h e l i s t m a t e r i a l l y . A s might be expected, most of t h e spec ies a r e widely d i s t r i b u t e d throughout t h e Indo-Pacific reg ion . S ix , however, a r e otherwise r e s t r i c t e d t o t h e Hawaiian I s l ands ; these a r e Trochus i n t e x t u s , Turbo a r t i c u Z a t u s , Ner i ta p i c e a , Cypraea granuZata, MacuZotriton spec ie s , and Pe r i s t e rn& crocea . Two o t h e r s , Strombus macuZatus and Cypraea s c h i Z d e r o m , a r e found i n Micronesia and Polynes ia , a s wel l a s i n t h e Hawaiian I s l ands , but not elsewhere. On t h e o the r hand, 12 of t h e spec ie s l i s t e d a r e uncommon t o r a r e i n t h e Hawaiian I s l ands , and three--PZanaxis zonatus , Mitra coZwnbeZZiformis, Parviperna dentifera--have not a s y e t been recorded from Hawaii. I n b r i e f , a l though t h e molluscan fauna of Johnston A t o l l shows an a f f i n i t y with t h a t of t h e Hawaiian I s l ands , it i s a l s o c l o s e l y r e l a t e d t o t h e fauna of Micronesia and Polynesia . A more thorough survey of t h e mollusks of Johnston A t o l l should he lp t o c l a r i f y i t s biogeographical pos i t i on . Annelida A t p resent only 12 spec ie s belonging t o e i g h t f a m i l i e s of Polychaeta a r e known from t h e lagoon waters a t Johnston A t o l l (Table 7 ) . Edmondson, e t aZ. (1925) l i s t e d s i x spec ie s co l l ec t ed during t h e 1923 TANAGER Expe- d i t i o n . Brock, e t a2. (1965) repor ted t h r e e spec ie s from 1963-1965 c o l l e c t i o n s . The p resen t paper l i s t s s i x spec ie s found i n t h e c o l l e c t i o n s of t h e National Museum of Natura l His tory and t h e Bernice P. Bishop Museum. Addit ional c o l l e c t i n g w i l l most l i k e l y r e s u l t i n an increased number of known spec ies from t h e a t o l l . Brock, e t aZ. (1965, 1966) showed t h a t dredging a t Johnston s l i g h t l y increased t h e number of polychaetes , but reduced t h e i r weight. Arthropoda Marine The lagoon waters a t Johnston A t o l l support a t o t a l of 75 spec ie s belonging to 20 f a m i l i e s of Crustacea (Table 8 ) . Edmondson, e t aZ. (1925) repor ted 59 spec ie s c o l l e c t e d by t h e 1923 TANAGER Expedit ion, while Brock, e t aZ. (1965, 1966) repor ted 12 spec ie s co l l ec t ed from 1963 through 1965. The present paper l i s t s 61 spec ie s found i n t h e c o l l e c t i o n s of t h e National Museum of Natural His tory and t h e Bernice P. Bishop Museum. Fur ther col- l e c t i n g a t Johnston A t o l l poss ib ly would r e s u l t i n a d d i t i o n a l known spec ies . Table 6. D i s t r i b u t i o n and abundance* of Mollusca from Johnston Ato l l Marginal. Johnston Sand Lagoon f i l l Gastropoda: N.W. Reef Isl-and Is land Sand Is land Trochidae Trochus i n t e x t m Reeve Turbinidae !Turbo articuZatus Reeve Ner i t i dae Nerita pZieata Linnaeus Nerita potita Linnaeus Nerita aZbieiZZa Linnaeus Nerita picea Recluz L i t t o r i n i d a e Littorina pintado Wood Littorina unduZata Gray Littorina coceinea (Gmelin) Planaxidae PZanaxis zonatus A. Adams Modulidae iYOduZus tectum (Lamarck) C e r i t h i i d a e RhinocZavis sinensis (Gmelin) Rhinoctavis articuZatus Adams & Reeve Cer i th im mtatum Sowerby Cerithiwn n e s i o t i c m P i l s b r y & Vanatta Hipponicidae Sabia conica (Schumacher) Strombidae Strombus macuZatus Sowerby Cypraeidae Cypraea granuZata Pease Cypraea heZvo2.a Linnaeus U Cypraea poraria Linnaeus U Cypraea caputserpentis Linnaeus Cypraea moneta Linnaeus U Cypraea macuZifer (Schilder) *V = Very abundant; M = Moderately abundant; U = uncommon. Table 6. (continued) Marginal Johnston Sand Lagoon f i l l Gastropoda (cont .) : N.W. Reef I s land Is land Sand Is land Cypraeidae (cont . ) Cypraea isabeZZa Linnaeus Cypraea carneo Za Linnaeus Cypraea schilderorum ( I r eda le ) Naticidae PoZinices (MamiZZa) melano- stoma (Gmelin) Cymatidae Cymatium (Septa) nicobaricum ~ E d i n g Cymatium (Septa) aquatize (Reeve) Cymatium (Septa) gemmatum (Reeve) Cymatium (Ranuzaria) muricinum RGding Distorsio anus Linnaeus Tonnidae Tonna (QuimaZea) pomum (Linnaeus) Muricidae MacuZotriton spec ie s Drupa m o m Rxding M Drupa r ic inus ( ~ i n n a e u s ) U MoruZa uva Rgd ing M MoruZa granuZata (Duclos) DrupeZZa ochrostoma, (B la inv i l l e ) Nassa septum Bruguiere Cora l l i oph i l idae CoraZZiophiZa vioZacea IZiener M QuoyuZa madreporarum (Sowerby) M Buccinidae Pisania ignea (Gmelin) Nassari idae Nassarius (Reticunassa) der- mestina (Gould) F a s c i o l a r i i d a e Peristernia crocea (Gray) Mi t r idae Mitra (StrigateZZa) coturn- beZZiformis Kiener Table 6. (continued) Marginal Johnston Sand Lagoon f i l l Gastropoda (cont . ) : N.W. Reef I s l and Is land Sand I s l and Turb ine l l idae Vasm turbineZZus (Linnaeus) U Conidae Conus pu Zicarius Hwass Conus nanus Sowerby Conus ra t t u s Hwass Conus v i t u l i nus Hwass Conus miles Linnaeus Conus flavidus Lamarck Terebridae Yerebra crenuZata Linnaeus Biva lv ia : Isognomonidae Isognomon perna ( ~ i n n a e u s ) Parviperna dent i fera (Krauss) Trapezidae Trapezium obzongwn (Linnaeus) T e l l i n i d a e Arcopagia (Seutarcopagiai scobinata ( ~ i n n a e u s ) Table 7 . Annelida from Johnston Atol l* Class Edmond son Brock Family e t aZ. e t a l . Present Species 1925 1965 Paper Polychaeta Amphinomedae Eurytlzoe compzanata (Pa l lus) Eurytkoe pacifica IZinberg Hermodice pinnata Treadwell C i r r a t u l i d a e CirratuZus sp. Eunicidae Eunice sp. Polynoidae HoZoZepideZZa nigropunctata (Horst) Phyllodocidae PhyZlodoce stigmata Treadwell Table 7 . (continued) Class Edmondson Brock Family e t aZ. e t a t . Present Species 1925 1965 Pap% Nereidae Nereis kobiensis Perinereis heZleri (Grube) Leodicidae Lysidice fusca Treadwell Lysidice sp. Leodocidae Leodice sp . *Taxonomic order fol lows t h a t i n t h e Annelida c o l l e c t i o n of t h e National Museum of Natural His tory . Table 8. Marine Arthropoda from Johnston Atol l* Class Brock Subclass Edmondson e t a l . Family e t aZ. 1965, Present Species 1925 1966 Paper Crustacea C i r r i p e d i a Lepadidae Lepas anati fera Linnaeus Malacostraca Squ i l l i dae [=Chlor ide l idae?] PseudosquiZZa oeulata ( ~ r u l l 6 ) X Palaemonidae CoraZZiocaris graminea (Dana) X Harpiliopsis depressus (Stimpson) x Jocaste Zucina (Nobil i ) X Pa Zaemone ZZa tenuipes Dana X Peridemenaeus tr identalus (Miers) X Gnathophyllidae GnathophyZtwn americanwn Guerin X Alpheidae Alpheus brevipes Stimpson Alpheus bucephalus ~ o u t i \ e r e X Alpheus clypeatus c o u t i k r e X Alpheus coZtumianus Stimpson X AZpheus crassimanus Hel le r X Alpheus diadema Dana X Alpheus grac i l i s Hel ler X i n c l . subsp. simplex (Banner) Alpheus ZeviuscuZus Dana X Appendix Table 8. (continued) Class Brock Subclass Edmondson e t aZ. Family e t aZ. 1965, Species 1925 1966 Alpheidae (cont .) AZpheus Zottini ~ u d r i n X X AZpheus paracrinitus Miers X AZpheus paragraciZis c o u t i k r e X SynaZpheus paraneomeris Couti2re X Hippolyt idae Lysmata paucidens (Rathbun) X Saron mamnoratus (Ol iv ier ) X Painur idae Panulirus marginatus (Quoy & Gaimard) Panutirus penciZZatus (Ol iv i e r ) X Scy l l a r idae Parribarms antarcticus (Lund) X Axiidae Axiopsis johnstoni Edmondson X Galatheidae Galathea spinosorostris Dana X Diogenidae AnicuZus anicutus (Fabricius) X CaZcinus eZegans (N. Milne-Edwards) X CaZcinus herbst i i d e Man X CaZcinus latens (Randall) X Dardanus haanii Rathbun Dardanus megistos (Herbst) Dardanus punctuZatus X Dynomenidae Dynomene hispida Desmarest X Calappidae CaZappa hepatica (Linnaeus) X Leuco s i i d a e flucia SpeCioSa Dana X Maj idae Perinea twnida Dana Schizophrys hiZensis Rathbun Pox tunidae Cataptrus inaequa Zis (Ra thbun) X Po~t~n t iS zongispinosus (Dana) X ThaZamita admete (Herbst) X ThaZamitoides quidridens A. Milne- X Edwards Xanthidae CarpiZius convexus (Forskal) X ChtorodieZZa asper Edmondson X Domecia hispida Eydoux & Souleyet X Etisus eZectra (Herbst) X Present Paper Table 8. (continued) Class Subclass Edmondson Family e t a l . Subspecies 1925 Xanthidae (cont .) Leptodius sanguineus (H. Milne- X Edwards) Leptodius waialuanus Rathbun X Lwcarpitodes biunguis (Ratbbun) X Liocarpilodes integerrimus (Dana) Liomere be ZZa (Dana) X Lophozozyms dodone (Herbst) Phymodius Zaysani Rathbun X Phymodius n i t i dus (Dana) X Pilodius aberrans (Rathbun) X PiZodius areoZata (H. Milne-Edwards) PZatypodia eydomi (A. Milne-Edwards) X Pseudoliomera speciosa (Dana) X Tetral ia gZaberrima (Herbst) X Tetral ia spp . Trapezia cymodoce (Herbst) Trapezia d i g i t a l i s L a t r e i l l e X Trapezia ferruginea L a t r e i l l e X Trapezia intermedia Miers X Trapezia maculata (MacLeay) ~ r a p e z i a rufopunctuta (Herbst) X Trapezia speciosa X Ocypodidae Ocypode Zaevis Dana Grapsidae Grapsus s tr igosus (Herbst) X Grapsus t enu icr i s ta tus (Herbst) X Pachygrapsus minutus A . Milne- X Edwards Pachygrapsus pZicatus ( H . Milne- Edwards) Hapalocarcinidae ~apaZocarcinus marsupiaZis X Stimpson Pseudocryptochirus crescentus X (Edmundson) Brock e t a2. 1965, Present 1966 Paper *Taxonomic order fol lows Chase (pers . cor res . ) . Very l i t t l e is known about t h e d i s t r i b u t i o n and abundance of ~ o h n s t o n ' s marine ar thropods. Brock, e t aZ. (1965, 1966), i n s tudying t h e e f f e c t s of dredging, d id r e v e a l t h a t dredging reduced t h e number and weight of xanthid c rabs and a lpheid shrimp inhab i t ing l i v i n g cort (vasiform Acropora) heads, but showed l i t t l e change i n c rab and shrimp popula t ions inhab i t ing l i v i n g c o r a l l i n e (PoroZithion) a lgae . T e r r e s t r i a l I n s e c t s t o t a l i n g 68 spec ie s of 35 f a m i l i e s were known from t h e i s l a n d s a t Johnston A t o l l by 1952 (Bryan, e t al . , 1926; Chilson, 1953). These a r e l i s t e d i n Table 9. POBSP personnel c o l l e c t e d i n s e c t s a t Johnston from 1963 through 1969; these c o l l e c t i o n s have n o t , a s y e t , been f u l l y i d e n t i f i e d . Table 9. I n s e c t s recorded from Johnston A t o l l ; adapted from Chilson (1953) O r thoptera B l a t t i d a e BZatteZa Z i tu r i cozz i s (Walker) C u t i l i a so ro r (Brunner) Pe r ip l ane ta americana (Linnaeus) PycnosceZus surinamensis (Linnaeus) Dermap t e r a Labiduridae AnisoZabis maritima (Gene) EuboreZZia annuzipes (Lucas) Mallophaga Menoponidae Austromenopon sternophiZum ( F e r r i s ) ; on t e r n . Thysanoptera Aeolo thr ip idae FrankZinieZZa suZfurea Schmutz Hemiptera Lygaeidae Nysius t e r r e s t r i s Usinger Geocoris punct ipes (Say) Reduviidae ZeZus r e n a r d i i Kolenat i Nabidae Nabis capsiformis Germar Gerr idae Halobates s e r i c e u s Eschscholtz Homoptera Aphididae Aphis gossyppi Glover Aphis medicaginis Koch Margarodidae I ce rya purchas i Maskell Pseudococcidae Pseudococcus ( c i t r i complex) ~seudococcus sp . perhaps c i t r i (Risso) F e r r i s i a n a v i r g a t a (Cockerell) Table 9. (continued) Homoptera (cont .) Coccidae Coccus sp. Coccus hesperidwn Linnaeus Saisse t ia nigra (Nietner) Saisset ia oZeae (Bernard) Diaspididae Aspidiotus Zataniae Signoret Chrysomphatus dictyospermi (Morgan) Pinnaspis sp. Pinnaspis strachani (Cooley) (of F e r r i s and Rao) Neuroptera Hemerobiidae Sympherobius sp . may be barber; Banks Lepidoptera Tineidae Tineota u t e re t t a Walsingham Ereunetis incerta Swezey Pterophoridae Trichopti lus oxydactytus (Walker) Phalaenidae Achaea janata (Linnaeus) Laphygma exempta (Walker) Coleoptera Dermestidae Dermestes a ter Degeer H i s t e r i d a e Carcinops quattuordecimstriata (Stephens) Anobiidae Lasioderma serricorne (Fabr ic ius) Tenebrionidae Alphitobius piceus (Oliver) Coccine l l idae Coetophora inaequatis (Fabricius) Scymnus Zoewii Mulsant Scymnus notescens Blackburn Curcul ionidae Dryotribus mimeticus Horn Macraney lus immigrans (Perkins) Hymenoptera Encyrt idae Aenasius advena Compere Leptomastk dactyZopii Howard Formic idae Sotenopsis geminata rufa (Jerdon) Monomoriwn pharaonis ( ~ i n n a e u s ) Cardiocondy Za sp . Tetramoriwn guineense (Fabr ic ius) Paratrechina ( N y Zanderia) sp . Paratrechina Zongicornis ( L a t r e i l l e ) Table 9. (continued) Hymenoptera (cont . ) Sphecidae ChaZubion bensaZense (Dahlbom) - - Vespidae PoZistes jfuscatus aur i fer Saussure Megachilidae Megachile fuZZawayi Cockerell Dip tera Syrphidae Simosyrphus ( ~ a n t k o ~ r m a ) grandicornis (Macquart) Xanthogrma scu t e t l a r i s (Fabr ic ius) Syrphus sp. Sarcophagidae Goniophyto bryani Lopes Sarcophaga s p . Sarcopkaga d m Thomson Sarcophaga barbata Thomson Cal l iphor idae Phaenicia sp. Muscidae Musca domestiea Linnaeus Musca dornestica v i c i m Macquart Atherigom excisa (Thomson) Mi l i ch i idae Desmometopa sp . Agromyzidae Agromyze pusiZZa Meigen Hippoboscidae OZfersia spini fera (Leach); from f r i g a t e b i r d s . Medically Important Species: Medically important ar thropods have, however, been s tudied (POBSP). These inc lude 2 t i c k s , 5 ch iggers , 2 n a s a l mi t e s , 23 b i t i n g l i c e , and 2 l ouse f l i e s . No f l e a s or mosquitoes a r e known from Johnston A t o l l . Ixodides: Two t i c k s , Ornithodoros capensis and Ornithodoros demark i (family Argasidae) , a r e known from Johnston A t o l l . A t h i r d t i c k , 1xodes laysanensis (family Ixodidae) , occurs on i s l a n d s i n t h e nor th-cent ra l P a c i f i c , but has not been recorded from Johnston A t o l l . It is expected, however, t o eventua l ly reach Johnston A t o l l because of b i rd movement between i s l a n d s i n t h e nor th-cent ra l P a c i f i c . Another t i c k , &odes merson i , which occurs on i s l a n d s i n t h e south-central P a c i f i c , i s not expected t o reach Johnston A t o l l because of a l a c k of b i rd movement between i s l a n d s i n t h e nor th-cent ra l and south-cent ra l P a c i f i c (Amerson, 1968). P h i l i p (1965) repor ted t h a t two v i r a l i s o l a t e s were made from Ornithodoros capensis Neumann taken from Sooty Tern and Brown Noddy n e s t s a t Sand I s l and . He s t a t e d t h a t t h i s a rbov i rus may be r e l a t e d t o "Hughes v i rus" which was i s o l a t e d by Hughes, e t a t . (1964) from Grnithodoros denmarki taken i n t e r n n e s t s on Bush Key, Dry Tortugas, F lo r ida . The a rbov i rus was l a t e r named "Johnston A t o l l v i rus" by C l i f f o r d , e t aZ. (1968), who noted t h a t i n a d d i t i o n t h e r e were a l s o two unnamed v i r u s e s from seabi rd t i c k s taken a t Sand I s l a n d , Johnston A t o l l . I n order t o o b t a i n a b e t t e r understanding of t h e r e l a t i o n s h i p between h i t h o d o r m capens i s and i t s h o s t s , a program was s t a r t e d i n January of 1965 by t h e POBSP t o monitor t h e t i c k populat ion on Sand I s l a n d , Johnston A t o l l , each month. Ber lese samples were taken (using a 5" x 5" x 1" metal sampler) a t random over t h e e n t i r e i s l a n d which had been divided i n t o sec t ions (Fig. 33). Ber lese samples f o r 1965 t o t a l e d 515 f o r the e n t i r e i s l and and 159 of t h e s e were p o s i t i v e f o r 0. capensis; t h e i n f e s t a t i o n r a t e was 31 percent . Since t h e o r i g i n a l p a r t of Sand I s l and is t h e most important t o t h e av i - fauna, 479 of t h e Berlese samples were taken from t h i s p a r t . The investa- t i o n r a t e f o r t h e o r i g i n a l p a r t during 1965 was 33 percent and Table 10 p resen t s t h e v a r i a t i o n i n each of t h e e i g h t a reas . The i n f e s t a t i o n r a t e was d e f i n i t e l y h ighes t (51 percent ) on t h e nor theas t peninsula (Areas H and K) and diminishes gradual ly toward t h e western p a r t of t h e i s l and . This i s shown i n F igure 33 by t h e d i s t r i b u t i o n of t h e p o s i t i v e samples i n t h e d i f f e r e n t a r e a s . Table 10. Ber lese sample data--0rnithodoros capens is i n f e s t a t i o n r a t e s f o r Sand I s l and , Johnston A t o l l , 1965. Areas A B C D E F H K T o t a l No. samples negat ive 7 21 43 58 57 48 44 43 321 No. samples p o s i t i v e 4 4 4 5 16 35 46 44 158 Tota l samples 11 25 47 63 73 83 90 87 47 9 Percent p o s i t i v e 36% 16% 9% 8% 22% 42% 51% 51% 33% This v a r i a t i o n i n i n f e s t a t i o n r a t e s i n t h e d i f f e r e n t a r e a s could be due t o seve ra l reasons: (1) eco log ica l d i f f e rences i n t h e va r ious a r e a s , (2) b i r d d i s t r i b u t i o n over t h e i s l a n d , and (3) man's d is turbance of t h e i s l and . Ecological d i f f e r e n c e s i n t h e var ious a r e a s a r e few s ince t h e vege ta t ion and s o i l i s s i m i l a r throughout t h e i s l and and t h e i s l and i t s e l f is small . A s w i l l be shown l a t e r , t h e b i rd d i s t r i b u t i o n , e s p e c i a l l y a t t h e peak popula t ion , covers the e n t i r e o r i g i n a l po r t ion of t h e i s l and . The USCG LORAN S t a t i o n was b u i l t i n 1960 and during cons t ruc t ion a l l old bu i ld ings , e t c . , l e f t from e a r l i e r a c t i v i t i e s , were bulldozed i n t o t h e surrounding lagoon. This a c t i v i t y undoubtedly d is rupted t h e s o i l and thus i n tu rn may have destroyed any t i c k s which were p resen t . The penin- s u l a , being f u r t h e r away from t h e c e n t e r of t h e d is turbance , was not severely d i s rup ted . This was v e r i f i e d when photographs taken i n 1923 were compared wi th 1963 photographs. It i s known t h a t t i c k s were very numerous on Sand I s l and a s e a r l y a s 1923 (Wetmore, ms.a). Bi-monthly i n f e s t a t i o n r a t e s f o r Sand-Johnston (Table 11) r evea l t h a t t h e r e was an inc rease i n t h e r a t e from January-February (32 percent) through May-June (43 percent ) and then a dec rease through t h e f a l l months t o a low of 17 percent i n November-December. T h i s seasonal f l u c t u a t i o n i s shown i n F igure 34 t o be co r re l a t ed wi th t h e seasonal populat ion of a l l t h e breeding b i r d s , mainly Sooty Terns, on t h e i s l and . B r i e f l y , t h e 1965 breeding c y c l e of t h e Sooty Terns was a s fol lows: l a t e October (1964)-- few observed; November (1964)--sharp inc rease i n n ight c a l l s ; December (1964)--increase i n numbers, f i r s t roos t ing on 14th ; l a t e January (1965) --170,000 b i r d s a t n i g h t , only a few dur ing day; February--thousands s i t t i n g on t h e i s l a n d by t h e l o t h , 25,000 incubat ing by t h e 15th , 40,000 by end of t h e month; mid-March--peak egg count of 140,000; April--82,000 chicks hatched by t h e 9 th , but numbers dropped t o 65,000 due t o m o r t a l i t y ; May--20,000 young were f l y i n g ; June--well over 50 percent of young were f l y i n g and l a r g e numbers l e f t t h e i s l a n d , only 50 eggs remained; July--most of t h e young l e f t t h e i s l a n d ; August--17,000 f i r s t h a l f , 2,700 by end of month; September-- few b i r d s remained; October--one chick p r e s e n t , not over 10 a d u l t s a day; November--night c a l l i n g increas ing; December--by mid-month b i r d s began s e t t i n g down on t h e i s l a n d , l a t e month r o o s t i n g to t a l ed 50,000 b i r d s . The a rea occupied by t h e Sooty Terns i s shown bi-monthly i n Figure 35. Inc rease i n t h e populat ion and breeding a c t i v i t y of t h e Sooty Terns during t h e spr ing months d i r e c t l y inf luenced t h e t i c k populat ion. The number of t i c k s per p o s i t i v e sample a l s o increased during t h i s period (Table 11) a s follows: January, February--3.5; March, April--9.4; May, June--8.0. During t h e summer and f a l l months t h e number of t i c k s per p o s i t i v e sample showed a decrease and then a n inc rease a s fol lows: J u l y , August--4.0; September, October--18.0; November, December--6.7. The in- c rease i n numbers during September and October i s poss ib ly due t o low sample s i z e (5) and t h e f a c t t h a t samples were purposeful ly taken i n p l aces where t i c k s were p l e n t i f u l ( i . e . , under rocks ) . The o v e r a l l average f o r 1965 was seven t i c k s per p o s i t i v e sample. The bi-monthly i n f e s t a t i o n r a t e s f o r t h e t h r e e major a r e a s (north- e a s t peninsula , e a s t h a l f , and west h a l f ) of Sand Is land a r e shown i n F igure 33 and Table 11. These r a t e s show t h a t t h e t i c k populat ions i n t h e d i f f e r e n t a r e a s f l u c t u a t e s i m i l a r l y t o t h a t f o r the e n t i r e i s l and (Fig. 34 ) , a s a l l t h r e e a r e a s reach a peak i n t h e May-June, July-August period. There i s , however, a v a r i a t i o n i n t h e i n f e s t a t i o n r a t e s i n each a r e a f o r each bi-monthly per iod . Th i s aga in shows t h a t t h e no r theas t peninsula a r e a not only has a higher r a t e o v e r a l l , but t h e r a t e was higher each bi-monthly period than t h e o ther a r e a s . For ins tance , during May- June, t h e r a t e on t h e peninsula was 89 pe rcen t , while on the e a s t po r t ion i t was 49 pe rcen t , and on t h e west p o r t i o n i t was 18 percent . A s has a l r eady been pointed out (and shown i n Figure 35) , t h e Sooty Terns and o t h e r spec ie s u t i l i z e almost a l l of t h e a v a i l a b l e land a r e a s during t h e spr ing and summer months, so t h e bi-monthly i n f e s t a t i o n r a t e v a r i a t i o n f o r t h e d i f f e r e n t a r e a s was n o t due completely t o t h e number of b i r d s us ing any p a r t i c u l a r a r e a of t h e i s l and . The 515 Ber lese samples taken on Sand-Johnston i n 1965 a r e shown by host-source i n Table 12 and demonstrate v a r i o u s n e s t i n f e s t a t i o n r a t e s f o r Ornithodoros capensis. On Sand I s l and t h e h ighes t n e s t i n f e s t a t i o n r a t e s occur i n t h e Brown Booby a t 50 percent and t h e Brown Noddy a t 49 percent . . . (D W 4 3 w u w w v. P. m w I in a g 0 u 3 s 2 6G c- Pi n T t 7 v. i-1. : E m i" . w " 2 m = z: D G rt % % i-1. i -1. 0 0 $ 3 1 ic H - P i G 'n lu (D H m m ' - ' C\ " rn n m i". p P a 3a "r (D H m m w L 'o " O 0 " * 3 Pi 4 H 0 (D fz n v . o n 1 F % z % % r P . 09 6 (D 13 W v. w w 3 a r . m a rn (D " in n rn 6 n v. lu fn b * P i c P 3 T t o a r . " H 8 3 0 1 Pi P O z g m rn au 0 m m 0 4 v . e o n n g q P m (D (D n o m o r e , P a ; % "r ( D O 0 P rn z Y o u . m 0 H H O 3 1 1 m m s H n , r. 8 2 % m m o a 01 0 r 2 * rn 0 .0 P . Pi I % @ m 0 S z :. Er n - 2 H PE RC EN T Figure 35. Areas used by Sooty Terns ( s t ipp led ) and Wedge-tailed Shearwaters Cbarred) on Sand I s l and , Johnston A t o l l , 1965. The Sooty Tern, by comparison, has an i n f e s t a t i o n r a t e of only 26 pe rcen t ; however, many of t h e samples labe led Miscellaneous L i t t e r ( r a t e 33 percent ) probably should be l i s t e d under Sooty Tern n e s t s s ince t h e spec ie s i s so widespread over t h e i s l and . The remaining i n f e s t a t i o n r a t e s a r e a s fol lows: Red-footed Booby 20 percent , Great F r iga teb i rd 20 percent , Red-tailed Tropicbird 7 percent , and Wedge-tailed Shearwater 5 percent , wi th t h e r e s t being 0 percent . Comparative d a t a from Green I s l and , Kure A t o l l , north- western Hawaiian I s l ands , a r e a l s o shown i n Table 12. Table 11. Ber lese sample data--bi-monthly Ornithodoros capensis i n f e s t a t i o n r a t e s f o r Sand I s l a n d , Johnston A t o l l , 1965. Areas A, B , C , and D JF MA M J J A SO ND T o t a l No. samples negat ive 1 20 4 2 7 10 4 9 129 No. samples p o s i t i v e 0 2 9 2 0 4 17 To ta l samples 1 2 2 5 1 9 10 53 146 Percent p o s i t i v e 0% 9% 18% 22% 0% 8% 12% Areas E and F No. samples negat ive 4 11 33 19 3 3 5 105 No. samples p o s i t i v e 2 7 3 2 8 0 2 5 1 Tota l samples 6 18 6 5 27 3 37 156 Percent p o s i t i v e 33% 39% 49% 30% 0% 5% 33% Areas H and K No. samples negat ive 21 8 2 43 1 12 8 7 No. samples p o s i t i v e 10 11 17 3 3 5 14 90 Tota l samples 31 19 1 9 76 6 26 176 Percent p o s i t i v e 32% 58% 89% 44% 83% 50% 51% A l l Areas No. samples negat ive 26 3 9 77 6 9 14 9 6 321 No. samples p o s i t i v e 12 20 58 43 5 2 0 158 T o t a l samples 38 59 135 112 1 9 116 479 Percent p o s i t i v e 32% 34% 43% 38% 26% 17% 33% No. of t i c k s per p o s i t i v e sample 3.5 9.4 8 . 0 4.0 18.0 6.7 7.0 Trombiculidae: Seven genera of 1 6 spec ie s of l a r v a l t rombicul id mi tes , commonly r e f e r r e d t o a s ch iggers , a r e known from POBSP c o l l e c t i o n s i n t h e c e n t r a l P a c i f i c (Brcnnan, 1965; Brennan and Amerson, 1971). Five s p e c i e s taken off s i x hos t spec ie s have been recorded from Sand I s l and . Neoschoengastia ewingi was taken off Golden Plover and Brown Noddy, a s wel l a s from l i t t e r taken i n t h e Sooty Tern nes t ing a r e a . Blankaartia merson i was recorded from t h e n a s a l c a v i t i e s of Bulwer's P e t r e l , Red-tailed Tropichi rd , Sooty Tern, and Brown Noddy, Guntherana domrowi was taken from Sooty Tern. Guntherana sp. was taken from a house mouse. Womersia strandtmanni was recorded off Sooty Terns. The f i r s t t h r e e spec ie s l i s t e d above a r e found both i n t h e north- and south-central P a c i f i c . Guntherana sp . i s lcnown only from Sand I s l and , Johnston A t o l l . Womersia strandtmanni a t Sand-Johnston i s a f i r s t and only record from t h e P a c i f i c ; i t i s a l s o known from t h e North American Gulf and A t l a n t i c coas t s . Table 12. Grnithodoros capens is i n f e s t a t i o n r a t e s from Berlese samples of hos t s ' n e s t s Green I., Kure A t o l l Sand I . , Johnston A t o l l 1964-1965 1965 Black-footed Albat ross Laysan Albat ross Wedge-tailed Shearwater Christmas Shearwater Bonin P e t r e l ~ u l w e r ' s P e t r e l Red-tailed Tropicbird Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd Sooty Tern Noddy Tern Black Noddy Hawaiian Monk Seal Polynesian Rat Misc. L i t t e r T o t a l s ii Do not occur. * re stir;^ a r e a . Rhinonyssidae: Amerson (1967) examined t h e n a s a l c a v i t i e s of 460 a d u l t and immature Sooty Terns taken throughout t h e i r 1965 breeding c y c l e on Sand I s l and , Johnston A t o l l , f o r Rhinonyssidae, o r n a s a l mites. Incidence of rh inonyss ids of two genera, Larinyssus and Sternostoma, i n a d u l t t e r n s increased during t h e egg-laying period and decreased (poss ib ly due t o feeding of young) a f t e r t h e eggs had hatched. Incidence i n young Sooty Terns was low (2 percent ) during t h e i r f i r s t 4 months, suggesting t h a t t r ans fe rence of mi t e s from a d u l t t e r n t o t h e i r young i s not very e f f i c i e n t . During t h e 5 t h month, however, t h e incidence r o s e t o 29 pe rcen t , suggest ing t h a t t h e mi t e s were elsewhere i n t h e hos t and they r e q u i r e time t o t r a v e l t o t h e n a s a l cav i ty . Mallophaga: Chilson (1953) l i s t e d one spec ies of Mallophaga, or b i t i n g l i c e , from t e r n s a t Johnston Ato l l . Amerson and Emerson (1971) recorded 23 spec ie s of 11 genera and two f a m i l i e s from POBSP c o l l e c t i o n s (Table 13) . Of t h e 12 b i rd h o s t s , a l l but two spec ie s were seabi rds ; t h e two were both shore b i r d s . Five Mallophaga spec ie s were taken from t h e Wedge-tailed Shearwater, four spec ie s were taken from t h e Sooty Tern, and t h r e e spec ie s were from t h e Brown Noddy. Hippohoscidae: Two spec ie s of hippoboscids, o r louse f l i e s , were recorded by POBSP personnel off f i v e spec ie s of s eab i rds a t Sand Is land (Maa, 1968). OZfersia aenescens was taken from t h e Great Fr iga te- b i r d , Sooty Tern, a s we l l a s from a Ber lese sample conta in ing l i t t e r . OZfersia spinifera was recorded from t h e Wedge-tailed Shearwater, Red- t a i l e d Tropicbird, Great F r i g a t e b i r d , and Brown Noddy. These two hippoboscid spec ie s a r e pan t rop ica l i n t h e P a c i f i c , Indian , and A t l a n t i c Oceans. Echinodermata A t o t a l of 37 spec ie s belonging t o 13 f a m i l i e s of Echinodermata a r e p resen t ly known from t h e lagoon waters of Johnston A t o l l (Table 14) . Edmondson, e t aZ.(1925) and Clark (1949), r e p o r t i n g pr imar i ly on m a t e r i a l co l l ec t ed by t h e 1923 TANAGER Expedition, each recorded 24 spec ie s . Brock, e t a l . (1965 , 1966) recorded s i x spec ie s from 1963- 1965 c o l l e c t i o n s . The present paper l is ts 26 spec ies found i n t h e c o l l e c t i o n s of t h e National Museum of Natural His tory and t h e Bernice P. Bishop Museum. Brock, e t aZ. (1965, 1966) s tudied t h e d i s t r i b u t i o n and abundance of conspicuous echinoderms a t Johnston A t o l l . Of n ine spec ie s s tudied i n 13 a r e a s , 'i'ripneusten g ra t i l l a was found i n 12 a r e a s and Heterocentrotus mmiZZa tus was found i n 10 a r e a s . They concluded t h a t dredging a f f ec t ed both d i s t r i b u t i o n and abundance of echinoderms. Ver t eb ra t e s The v e r t e b r a t e s of Johnston A t o l l a r e wel l known. Extensive eco log ica l s t u d i e s have been made on t h e f i s h e s , b i r d s , and mammals. Although the spec ie s composition of r e p t i 1 . e ~ i s wel l known, very l i t t l e i s known about t h e i r populat ions. T a b l e 1 3 . Mallophaga c o l l e c t e d a t Sand I s l a n d , J o h n s t o n A t o l l by t h e POBSP; adap ted from Amerson and Emerson (1971) Suborder Family S p e c i e s Host I s c h n o c e r a P h i l o p t e r i d a e Hatipeurus heratdieus HaZipeums pacificus Naubates harrisoni Pectinopygus graciZicornis Pectinopygus su Zae Quadraceps b i r o s t r i s Quadraceps charadrii hospes Quadraceps impar @adraceps separatus Quadraceps s p . Saemundssonia albemarlensis Ablycera Menoponidae ActornithophiZus incisus ActornithophiZus piceus piceus ActornithophyZus s p . Austromenopon a t r o f u l v m Austromenopon squaturoZae ColpoccephaZwn angulaticeps LSidmannieZZa aZbescens Procellariphaga paiZuZa ProceZZariphaga s p . Phoenix P e t r e l Wedge-tailed Shearwater Wedge-tailed Shearwater Grea t F r i g a t e b i r d Red-footed Booby Sooty Tern Black-be l l i ed P l o v e r Wandering T a t t l e r Brown Noddy Gray-backed T e r n Sooty Tern Red- ta i l ed T r o p i c b i r d Wedge-tailed Shearwater Wedge-tailed Shearwater Brown Noddy Sooty T e r n Brown Noddy Sooty Tern Black-be l l i ed P lover Grea t F r i g a t e b i r d Blue-faced Booby Wedge-tailed Shearwate r Phoenix P e t r e l T a b l e 14. Echinodermata from J o h n s t o n A t o l l * C l a s s Brock S u b c l a s s Edmondson e t a l . Family e t a;i. C l a r k 1965, P r e s e n t S p e c i e s 1925 1949 1966 Pa~e_r Echinoi.dea Diademat i d a e Diadema s p . X Eehinothrix cazamaris ( P a l l a s ) X Echimthrix diadema (Linnaeus) X X Echinometr idae Echinometra mathaei ( d e B l a i n - X X v i l l e ) Echniometra obZongu (de Bla in - X X v i l l e ) Table 14. (continued) Class Subclass Edmondson Family e t aZ. Species 1925 - Echinometridae (cont .) Echinostrephus aciculatus X A. Agassiz Echinostrephus molaris (de B l a i n v i l l e ) Heterocentrotus mammiZlatus 7.7 A, (Linnaeus) Heterocentrotus trigonarius X (Lamarck) Toxopneustidae Tr'ripneustes gratiZZa (Linnaeus) :< Briss idae Brissus Zatecarinatus (Leske) :< Holothuroidea Holothuri idae Actinopyga mauritiana (Quay & Gaimard) Actinopyga obesa (Selenka) Actinopyga sp . Holothuria atra Jaeger HoZothuria d i f f i c i l i s semper Holuthuria h i l l a (Lesson) HoZothuria impatiens (Forskal) Holothuria pardaZis Selenka Holuthuria parvuZa (Selenka) Synaptidae Chiridota r ig ida Semper Opkeodesoma spectabi l is Fisher PoZypZectana k e f e r s t e i n i i (Selenka) Stel l -eroidea Asteroidea Oreas ter idae CuZcita arenosa P e r r i e r CuZcita novaeguineae Muller & Torschel Ophidiaster idae Linckia mutt i fora (Lamarck) Acanthaster idae Acanthuster pZanci (Linnaeus) Mithrodiidae Mithrodia bracileyi V e r r i l ~ l Mithrodia f i sher i ~ o l l y Brock e t a l . Clark 1965, Present 1949 1966 Paper Appendix Table 14. (continued) Class Brock Subclass Edmondson e t a l . Family e t a l . Clark 1965, Present Species 1925 1949 1966 Paper S t e l l e r o i d e a (cont .) Ophiuroidea Ophiactidae Ophiactis savignyi X X (Muller & Troschel) Ophiocomidae Ophiocoma erinaceus Muller & Troschel X X Ophiocoma pica (Huller & X Troschel) Ophiocoma sp. Ophiocomella c l ippertoni OphiocomeZ Za sexradia (Duncan) Ophiodermatidae Distichophis c la rk i Ophiopeza spinosa (Ljungman) "Taxodermic order fo l lows Hyman (1940), Durham, e t uZ. (1966a, 1966b), and Beaver, e t aZ. (1967). F ishes The f i s h fauna of Johnston A t o l l is wel l known and i s he re in separated i n t o two ca t egor i e s : pe lagic f i s h e s and inshore f i s h e s . I n the i n t e r e s t of cons is tency , taxonomic order fo l lows t h a t used by Gosline (1955) and Brock, e t a l . (1965, 1966), whose i d e n t i f i c a t i o n and nomenclature fol low Schul tz , e t aZ. (1953). Pe lagic F ishes Numerous l a r g e pe lag ic f i s h e s occur around Johnston A t o l l . No extens ive spec ie s l i s t e x i s t s f o r t h i s a r e a , but f i s h e s here include tuna (wahoo, sk ip jack , and ye l lowfin) , barracuda, and sharks (Chapman, 1946; Halstead and Bunker, 1954a). Two sharks , not included i n t h e inshore reef fauna but known from the re , include t h e white-tipped shark , Triaenodon obesus (family Triakidae) and t h e grey sand shark , Carcharhinus menisorrah (family Carcharhinidae) . Addi t ional spec ies of sharks a r e most l i k e l y t o occur i n t h e lagoon. Barracuda and tuna a l s o a r e known from t h e lagoon waters (Brock, e t a l . , 1965, 1966). Inshore F ishes A t o t a l of 194 spec ie s of inshore f i s h e s a r e known from Johnston A t o l l (Table 15 ) . Of these 194 spec ie s , 27 were repor ted by Smith and Swain (1882), of which f i v e were described a s new. Fowler and Ba l l (1925) l i s t e d 72 spec ie s c o l l e c t e d i n 1923 by t h e TANAGER Expedition; one of t hese was described a s new. Nine spec ie s , t h r e e of them new, were repor ted by Schul tz , e t az. (1953). From c o l l e c t i o n s taken i n 1951, Halstead and Bunker (1954a) l i s t e d 60 spec ies and Gosline (1955) recorded 111 spec ie s . Brock, et al . (1965, 1966) repor ted 143 spec ie s from c o l l e c t i o n s talcen during August 1963 through August 1965. A s a mat ter of f u r t h e r h i s t o r i c a l i n t e r e s t , 109 spec ies were known by 1954, 49 spec ie s not previous ly repor ted were added by 1955, and a n a d d i t i o n a l 36 spec ie s were added by 1966. Gosline (1955) suggested t h a t t h e Johnston A t o l l f i s h fauna is made up of four components: (1) endemics, ( 2 ) f i s h t h a t have made Johnston a s topping poin t on t h e i r migra t ions no r th , (3) f i s h t h a t have made Johnston a s topping point i n t h e i r southward t r a v e l s , and (4) t h e pe lag ic f i s h t o whom Johnston is of l i t t l e o r no s ign i f i cance . Only two spec ie s of Johnston f i s h e s have not been taken elsewhere. These a r e Centropyge nigrioceZZus and C. f Z m e u s , both b u t t e r f l y - f i s h e s ; n e i t h e r a r e abundant a t Johnston (Gosline, 1955). Since only two spec ies a r e endemic, i t would appear t h a t Johnston is not i s o l a t e d i n t h e evolu t ionary sense. I n c o n t r a s t , according t o Gosl ine, near ly one half of t h e Line I s l and inshore f i s h e s d o not occur i n Johnston or Hawaiian waters . Because of t h e wide s t r e t c h e s of deep water between the northernmost Line I s l a n d s and Johnston, Johnston A t o l l i s comparatively i s o l a t e d from t h e south . ~ o h n s t o n ' s f i s h fauna i s much more c l o s e l y a l l i e d t o t h a t of t h e Hawaiian I s l ands . This i s seen i n t h e f a c t t h a t t h e major i ty of t h e t r o p i c a l spec ie s p re sen t a t Johnston a r e a l s o found i n Hawaii. The present-day Hawaiian f i s h fauna i s thought t o have been derived from more t r o p i c a l waters . Yet presence of many tropical . spec ie s a t Johnston t h a t a r e now unknown from Eawaiian waters would seem t o i n d i c a t e t h a t t h e r e i s a l i m i t t o how many warm water spec ies Hawaii can absorb. Eventual ly i t i s expected t h a t more t r o p i c a l spec ies w i l l e s t a b l i s h themselves i n Hawaiian waters . Gosl ine has suggested t h a t Johnston A t o l l was probably t h e o r i g i n a l por t of en t ry of Hawaii's inshore f i s h fauna . D i s t r i b u t i o n and Abundance Within t h e A t o l l Halstead and Bunker (1954a) genera l ized t h e f i s h d i s t r i b u t i o n a t Johnston and divided t h e a t o l l i n t o t h r e e zones: (1) nor thern (periphe- r a l ) r ee f a r e a , (2) southern (shoal) reef a r e a , and (3) bank (lagoon) shoals . The northern reef a rea was charac ter ized by scombroid f i s h e s , barracuda, sharks , and o the r pe l ag ic spec ie s l i v i n g on t h e seaward (open-water) s i d e of t h e reef and eagle-rays, moray e e l s , b u t t e r f l y , s q u i r r e l , surgeon, damsel, surmul le t , pu f fe r , and f i l e f i s h e s on t h e lagoon s i d e . The southern r ee f a rea was not examined but a l a r g e shark populat ion was thought t o e x i s t i n t h e open water; f i s h spec ie s were bel ieved t o be fewer i n number and v a r i e t y here , compared t o t h e nor thern reef a rea . The bank shoals o r lagoon a rea was charac ter ized by: moray e e l s , wrasse, p a r r o t , coronet , surgeon, b u t t e r f l y , s q u i r r e l , damsel, and puf fe r f i s h e s i n t h e patch reef po r t ion ; f lounders , b lennies , surmul le t , pompano, pu f fe r s , pomacentrids, s t i n g r a y s , and t r i g g e r f i s h e s i n t h e sandy a reas ; and trumpet, p a r r o t , damsel, pompano, t r i g g e r , and b u t t e r f l y f i s h e s i n t h e wreckage o r dump a rea t o t h e southwest of Johnston Is land . A s p a r t of an extens ive study on t h e e f f e c t s of dredging a t Johnston, Brock, e t a t . (1965) s tudied t h e d i s t r i b u t i o n and abundance of 75 s p e c i e s a t n ine l o c a l i t i e s w i th in t h e lagoon during August 1963 t o June 1964 (Fig. 36) . Areas 1, 2 , and 4 were near t h e marginal reef JOHNSTON ISLAND AND REEF nlack - recent ly formed land areas. Cross hatch - areas of reef a l tered by recent dredging. S t i p l i n g - land area prior t o recent dredging. D o t s - area often covered hy turbid w a t e r during the dredging operation (incomplete i n soulliriest area where turb id i ty extended f a = our t o s e a ) . Ildtclling - trapping umbered dots - s t a t i o n s studied. A - ~ o h n - s t o n Is land, 8 - s a n d ~ s l a n d , c - riast island, 11 - Nurtli Is land, E - Nortli Island Trap Area, 3 0 Figure 36. F i s h c o l l e c t i o n s t a t i o n s , Johnston Ato l l , 1963-1964 CBrock, e t a l . , 1965). and each contained higher numbers of spec ie s , r e spec t ive ly 59, 45, and 43 spec ies (mean = 49 s p e c i e s ) , than a r e a s 3 , 5 , 6 , 7 , 8 , and 9 i n the lagoon proper. Numbers of spec ie s i n t h e lagoon a r e a s ranged from 28 t o 39 spec ie s , wi th t h e mean being 33 spec ie s . Actual numbers of i nd iv idua l s were a l s o h ighes t i n t h e marginal reef zone; however, r a t i o s of numbers of spec ie s t o numbers of i nd iv idua l s appear to be higher i n genera l i n t h e lagoon zone. Commonness of spec ie s , based on t h e number of a r e a s each were found i n , show t h a t of t h e 75 spec ie s , s i x spec ie s were found i n a l l n ine a r e a s . The most abundant spec ie s was Acanthus sandvieensis; i t was found i n a l l a r e a s and was dominant i n f i v e a r e a s . The next t h ree more abundant spec ie s , i n o rde r , were Scams sordidus, Ctenochaetus s t r igosus , and Acanthurus achiZZes; each was dominant i n t h r e e a r e a s a s wel l a s found i n a l l a r e a s . Twelve spec ie s were found only i n one a r e a ; t hese were considered r a r e i n abundance. Brock, e t aZ. (1966) continued t h e i r d i s t r i b u t i o n and abundance s t u d i e s during August 1964 t o August 1965. They added four new study s t a t i o n s (see a r e a s 10, 11, 12, and 13, Fig. 32) and examined e f f e c t s of r e c e n t l y completed dredging opera t ions . They co l l ec t ed f i s h e s i n t h e bottom and s i d e s ( c l i f f s ) of dredged a r e a s , a s wel l a s non-disturbed reef a r e a s . I n gene ra l , t h e c l i f f s were barren of f i s h : two areas had no f i s h and two had t h r e e or n ine spec ie s . Bottoms of t h r e e a r e a s were a l s o q u i t e d e s o l a t e : one had no spec ie s , one had t h r e e spec ies , and t h e o ther had e i g h t spec ie s . The remaining bottom a rea had 25 spec ie s , one more than t h e 24 spec ies found i n t h e ad jacent r e e f . In genera l , t h e remaining non-dredged reef por t ion had f a i r numbers of spec ies : 23, 19 , and 14. Brock, e t 0 2 . (1965) found no e f f e c t s of dredging on f i s h e s i n t h e i r work through June 1964. But Brock, e t aZ. (1966) d id f ind the f i s h fauna adverse ly a f f ec t ed by dredging from August 1964 through August 1965. By resurveying a r e a s 4 through 8 they were a b l e to compare numbers and abundance of spec ie s . The number of spec ie s of f i s h observed during 1965 was about 50 percent l e s s ' than t h a t observed during 1964 f o r s t a t i o n s 4 and 5 , and about 10 percent l e s s than s t a t i o n s 6 , 7 , and 8 . From 2 t o 13 spec ie s (mean = 7 ) new t o each a r e a were a l s o found. I f these were subt rac ted from t h e 1965 t o t a l s , then t h e d i f f e r e n c e between years would even be higher . Brock, e t a l . (1966) a l s o noted t h a t t h e number of spec ie s r a t ed a s common o r dominant was l e s s f o r a l l s t a t i o n s (except one changing from common t o dominant i n s t a t i o n 8) f o r 1965 a s compared t o 1964. Their da t a suggest t h a t while t h e t o t a l number of spec ie s observed fo r t h e two years changed very l i t t l e f o r s t a t i o n s 6 , 7 , and 8 , t h e i r abundance changed s i g n i f i c a n t l y . Table 15. Inshore f i s h e s recorded from Johnston A t o l l Brock, e t a z . , Brock, e t aZ. Smith and Swain 1882 1965 1966 Fowler and B a l l 1925 Gosline Aug. Dec. 1963- Aug. 1964- Halstead and Bunker 1954 1955 1963 June 1965 Aug. 1965 Myliobatidae (Eaglerays) Aetobaatus nminar i Synodontidae (Lizardf i shes ) Saurida graciZZis Synodus binotatus Synodus vai^iegatus Congridae (Conger Eels) Conger marginatus (=C. noordzieki i ) Ophichthidae (Snake Eels) Brachysomophis sauropsis Leiu~anus semicinctus ~ep t enche t y s ZabiaZis Muraenchetys cookei Muraenichthys gymnotus Muraenichthys schul tze i Myrichthys bZeekeri i4yyrichthys macuZosus PhyZZophichthus xenodontus Schuttzidia joh-nstonensis Xenocongridae (Fa lse Moray Eels) kupich thgs diodontus Noringuidae (Worm Eels) Moringua macrochir Table 15. (continued) Brock, e t aZ. , Brock, e t aZ. , Smith and Swain 1882 1965 1966 Fowler and Ba l l 1925 Gosline Aug. Dec. 1963- Aug. 1964- Halstead and Bunker 1954 1955 1963 June 1965 Aug. 1965 Muraenidae (Moray Eels) Anarchias aZZardicei A.mchias cantonensis Anarchias Zeucums Echidna Zeucotaenia Echidna po Zyzona Ec hidim unico Zor Echi&fia zebra Gymnothorax s p . Gymnothorax buroensis Gymfiothorax euro s tus Gymnothorax gracilicaudus Gymnothorax javanicus Gymnothorax meleagris Gymnothorax moZucsensis Gymnothorax pictus Gymnothorax undutatus iiabuZa fuscomaeuZata Uropterygius sp . Uropterygius fuscoguttatus Uropterygius knight i Uropterygius poZyspiZus Uropterygius supraforatus (=U. dentatus) Uropterygius t igr inus Belonidae (Needlef i shes ) BeZone pZatyu.a Hemiramphidae (Halfbeaks) Hyporhamphus acutus Table 15. (continued) Brock, e t aZ. , Brock, e t a l . , Smith and Swain 1882 1965 1966 Fowler and Bal l 1925 Gosline Auz. Dec. 1963- AuP.. 1964- - Halstead and Bunker 1954 1955 1963 June 1965 Aug. 1965 Exocoetidae (Fly ingf ishes) CypseZurus peociZopterus CyhseZurus simus Aulostomidae (Trumpetfishes) A~20st0m.s chinensis X ~ i s t u l a r i i d a e (Cornetf ishes) Fistularia petimba X Syngnathidae (Pipef i shes ) Doryrhphus me Zanop ieura Holocentridae (So ld ie r f i shes or Squi r re l f i shes ) HoZocentrus Zacteoguttatus HoZocent~ns microstoms Ho Zocentrus s m a r a HoZocentms sp in i fer HoZocentwi.s t i e r e HoZotrachys Zima Myriprist is argyrom.s ?4yriprist is beri7dti Apogonidae (Cardinal Fishes) Apogon ery t h r i - i s Apogon maneserius Apogon snyderi Apogon waikiki Pseudamiops gracizicaude Table 15. (con t inued) Brock. e t a t . . Brock. e t a t . . Smith and Swain 1882 1965 1966 Fowler and B a l l 1925 G o s l i n e Aug. Dec. 1963- Aug. 1964- B a l s t e a d and Bunker 1954 1955 1963 J u n e 1965 Aug. 1965 K u h l i i d a e (Aholeholes) KuhZia marg+nata Grammistidae (=Pseudo- chromidae) Pseudogroma poZyacantha P r i a c a n t h i d a e (Big Eyes) Priacanthus cruentatus S e r r a n i d a e (Sea Bass) Pristipomoides s iebo td i i L u t j a n i d a e (Snappers) Aphareus furcatus Kyphosidae (Rudderf i s h e s ) Kyphosus bigibbus Xyphosus vaigiensis Mul l idae (Sunmulle ts . Goat- f i s h e s ) iMulZoidickthys aur i f t oma ?4uZZoidickthgs smoensis Pampeneus b&rberinus Parupeneus bi fasciatus Parupeneus chryserydros Perupeneus crass i tabris Parupeneus mult i fasciatus Pampeneus t r i f a sc ia tu s Table 15. (continued) Brock, e t a l . , Brock, e t a t . , Smith and Swain 1882 1965 1966 Fowler and Ba l l 1925 Gosline Aug. Dec. 1963- Aua. 1964- Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 C i r r h i t i d a e (Hawkf i shes ) AmbZycirrhites bimacuZa Cirrhi tus atternatus Cirrhitus pinnuZatus Paracirrhites arcatus Paracirrhites fors ter i Carangidae (Pompano, Ulua, Papio) Caranyoides ferdau Caram ascensionis Caram dasson Caram gymnostethoides Caram lugubris Caram meZampygus C . (=Gnathanodon) speciosis Scornheroides sanct i -petr i Trachurops cmunenophthalmus Pomacentridae (Damselfishes) Abudefduf imparipennis Abudefduf phoenixensis Abudefduf sordidus Chromis leucurus Chromis vanderbizt i Dascy ZZus aZbiseZZa Dascy Z Zus margimtus PZectroglyphidodon johns- t on iams Table 15. (continued) Brock, e t aZ., Brock, e t a z . , Smith and Swain 1882 1965 1966 Fowler and B a l l 1925 Gosline Aug. Dec. 1963- Aug. 1964- Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 Labridae (Wrasses) Bodianus biZunuZatus CheiZinus rhodochrous CheiZio inermis CheiZio f tauauit tata Coris gmimardi EpibuZus ins id ia tor Gomphosus varius ( inc ludes G. t r i c o l o r ) HaZickoeres o r n a t i s s i m s Labroides phthirophagus ?$ovacuZichthys taeniourus Pseudocheitinus hexataenia PseudocheiZinus octotaenia PseudocheiZinus tetrataenia StethojuZis azbovit tata StethojuZis m i Z l a r i s TkaZassoma baZlieui TkaZassoma fuscwn TkaZassoma duperreyi TkaZassoma Zutescens TkaZassoma purpurem ThaZassoma quinquevittata ThaZassoma umbrostigma Scaridae (Pa r ro t f i shes ) Calotomus spinidens (=C. sandvieensis) Scams c y a n o g r m s Scams dubius Scams duperreyi Table 15. (continued) Brock, e t aZ., Brock, e t aZ., Smith and Swain 1882 1965 1966 Fowler and Ba l l 1925 Gosline Aue. Dec. 1963- Aue. 1964- ., ~ Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 Scaridae (cont .) Seams erythrodon Scams f o r s t e r i Scarus perspiciZZatus Scarus sordidus Scams sp. (grey) Scarus sp. (blue-green) Chaetodontidae (But te r f ly- f i s h e s ) Centropyge f lameus Centropyge nigrioceZ Zus Chaetodon auriga Chaetodon citrineZZus Chaetodon ephippiwn Chaetodon muZticinctus Chaetodon ornatissimus Chaetodon quadrimacu Zatus C3zaetodon reticuZatus Chaetodon t r i f a s c i a t u s Chaetodon unimacuZatus Chaetodon eoZ Forcipiger Zongirostris Hermituurichthys thompsoni Megaprotodon striganguzus Zanclidae (Moorish Ido l s ) ZancZus cornutus Acanthuridae (Surgeonfishes) Acanthurus achi l Zes Acanthwus gZaucopareius Table 15. (continued) Brock, e t a t . , Brock, e t a l . , Smith and Swain 1882 1965 1966 Fowler and Bal l 1925 Gosline AUK. Dec. 1963- AUR. 1964- - Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 Acanthuridae (cont. ) Acanthurus guttatur Acanthurus mata Acanthums nigroris (=A. elongatus) Acantkurus oliuaceus Acanthurus sandvieensis Ctenochaetus cyanopt ta tus Ctenochaetus hawaiiensis Ctenochaetus s t r i a tu s Ctenochaetus strigosus Naso Zituratus Naso unicornis Zebrasoma flavescens Zebrasoma ue Z i ferwn Eleo t r idae (Sleepers) Euiota u i r i d i s Gobiidae (Gobies) Bathygobius fuseus GnathoZepis mnjerensis Hazeus unisquamis Zonogobius farcimen Blenniidae (Blennies) Cirripectes uarioZosus ExaZZias breuis IstibZennius gibbifrons (=SaZarias gibbifrons) Table 15. (continued) Brock, e t a l . , Brock, e t aZ., Smith and Swain 1882 1965 1966 Fowler and Ba l l 1925 Gosline Aug. Dec. 1963- Aug. 1964- Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 Erotu l idae (Brotu l ids) BrotuZa townsendi Mugilidae (Mullets) Neomyxus chaptazi i Sphyraenidae (Barracudas) Spbaena japonica Polynemidae (Threadf in s ) PoZydactyZus s e x f i t i s Scorpaenidae (Scorpion Fishes) ,Scorpaena baZlieui Scorpaena coniorta Scorpaenodes parvipinnis Bothidae (Flounder or F l a t f i s h e s ) Bothus mancus X Echeneidae (Renoras) Remora remora B a l i s t i d a e (Triggerf i shes ) BaZistes bursa MeZichthys buniva jMeZichthys ringens MeZiehthys vidua Rhinecaithus acuZeatus Table 15. (continued) Brock, e t a l . , Brock, e t a t . , Smith and Swain 1882 1965 1966 Fowler and Ba l l 1925 Gosline Aug. Dec. 1963- Aug. 1964- Halstead and Bunker 1954 1955 1963 June 1963 Aug. 1965 Monacanthidae ( F i l e f i s h e s ) Alutera scripta Amanses carolae Amanses sandwichiensis Pervagor rnelanocephatus Pervagor spilosoma Ostrac iont idae (Trunkf i shes ) Kentrocarpus hexagonus X Ostracion cubicus X Ostracion Zentiginosus X Ostracion meleagris x Ostmcion soZorensis X Tetraodontidae (Puffers ) Arothron meleagris Canthigas ter idae (Sharp-nosed Puf fe r s ) Canthigaster jactator X Diodontidae (Box Fishes) Diodon hys t r ix Tota l Species New t o A t o l l Old Species Not Seen Cigua te r i c F ishes The f i r s t i d e n t i f i e d cases of ciguatera- type f i s h poisoning occurred a t Johnston A t o l l i n 1950. According t o Halstead and Bunker (1954a), t h e r e were about 20 cases of c igua te ra poisoning between May 1950 and May 1951. F ishes thought by i s l a n d workers t o be dangerous t o e a t included: p u f f e r s (Tetraocontidae) , t r i g g e r f i s h ( B a l i s t i d a e ) , s a b o t i (Kuhliidae) , ulua (Carangidae) , "tuna" (probably Euthynnus ya i t o , a sk ip j ack ) , "red or blue t o o t h l e s s snapper" (?) , moray e e l s (Muraenidae) , and surmul le t (Mullidae) . Following t h i s 1950 poison outbreak, Halstead and Bunker (1954a) s tudied t h e c igua te ra problem a t Johnston Ato l l . They c o l l e c t e d f i s h e s i n May, October and November 1951. They found t h a t of 60 spec ie s (211 specimens) of 21 f a m i l i e s t e s t e d , 47 spec ie s (78 pe rcen t ) , and 98 specimens (46 percent ) were t o x i c (Table 16 ) . Both the musculature and v i s c e r a of specimens were found t o be t o x i c . Although t h e bioassay method used i n t h i s 1954 study was l a t e r found t o be of ques t ionable va lue (Banner, e t a l . , l 960) , numerous spec ie s of inshore f i s h e s were tox ic a s evidenced by t h e numerous cases of c igua te ra poisoning r e - ported (Banner and Hel f r ich , 1964; Brock, e t a l . , 1965). By 1963, however, t h e poison problem appeared t o have subsided (Banner and He l f r i ch , 1964). I n August 1963, 21 spec ie s (224 specimens) of 11 f a m i l i e s were examined f o r poison (Table 16) by Brock, e t a l . , (1965). Of t h e s e 21 spec ie s , only two (10 percent ) were tox ic : t h e white-tipped reef shark Triaenodon obesus (11 percent) and t h e l a r g e moray e e l Gymnothorm javanicus (80 pe rcen t ) . By interviewing i s l and cons t ruc t ion workers (mostly from Hawaii), they a l s o discovered t h a t many v a r i e t i e s of lagoon f i s h e s were ea t en l o c a l l y . Most "expressed a wi l l i ngness t o e a t any of t h e Johns ton . . . f i shes except b lack u lua , moray e e l s , and sharks." Brock, e t a l . (1965: 23) described t h e s i t u a t i o n a t Johnston A t o l l a s "...what might be expected near t h e te rminat ion of a period of occurrence of c igua te ra poisoning i n f i s h e s . Such a period would become f i r s t evident by t h e herbivorous spec ie s becoming tox ic . Following t h e i n i t i a l s t a g e both herbivorous and carnivorous spec ie s would be t o x i c , t h e l a t t e r through predat ion of t h e herb ivores . This period may l a s t f o r a number of years . Its terminat ion would be marked f i r s t by t h e absence of young tox ic herb ivores , followed by t h e absence of young t o x i c carn ivores . The r e s i d u a l e f f e c t s would be evident through t h e occurrence of c igua te ra tox in only i n t h e l a r g e , long l ived predators . Once a f i s h becomes tox ic it appears t o remain so f o r long per iods of t ime even though i t does not cont inue t o consume t o x i c prey. However, t h e t o x i n locked up i n t h e bodies of t h e l a r g e r predators can r e c y c l e back i n t o o the r predators e i t h e r l a r g e o r smal l upon t h e occasion of t h e i r dea th from old age or d i s e a s e or some o ther cause." Randall (1958) suggested t h a t t h e tox in r e spons ib le f o r c igua te ra was produced by a lgae , poss ib ly a blue-green a lgae , which occurred e a r l y and abundantly during t h e success ional invasion of a newly denuded s u b s t r a t e by a lgae . The a l g a e would be eaten by herbivorous animals and these , i n t u r n , by carnivorous animals. Brock, e t aZ. (1965) noted t h a t i f Randal l ' s hypothesis was v a l i d , a s u b s t a n t i a l i nc rease i n t h e number and spec ies of t ox ic f i s h , beginning with the herbivorous spec ie s , should fol low t h e dredging opera t ions a t Johnston which began i n August 1963. A t the beginning of t h i s dredging, none of these herbivorous spec ie s was found t o be tox ic ; only the l a r g e r predacious sharks and e e l s were toxic . Ciguatera poison cases , i n f a c t , d i d continue (Brock, a t aZ., 1966). Several poisonings (one se r ious , t h e o the r s mild) were reported i n May 1964 involving a predacious b lack u lua Caranx meZampygus. I n a d d i t i o n , two r a t h e r s e r ious cases occurred i n August 1965, with seve ra l spec ies of reef f i s h e s involved. Likewise, a s l i g h t increase i n numbers of t ox ic f i s h e s occurred (Brock, e t aZ., 1966). Of 38 spec ie s examined during August 1964 t o August 1965 (number of specimens unknown), s i x spec ies of f i v e f a m i l i e s (16 percent ) were t o x i c . A s i n the 1963 s tudy, t h e moray e e l Gymnothorax javanicus was most t ox ic a t 48 pe rcen t , wi th t h e white-tipped reef shark Triaenodon obesus second a t 19 percent t ox ic (Table 1 6 ) . Another shark species--the grey sand shark Carcharhinus menisorrah--was a l s o found t o be toxic (11 pe rcen t ) ; t h i s s p e c i e s was not t ox ic i n the 1963 t e s t s . Three o ther species--al l herbivorous--not t ox ic i n 1963 were a l s o tox ic i n t h e 1964-1965 t e s t s . They were Ctewchaetus s t r igosus , a surgeon f i s h , and Melichthys buniva and M . v idua, both t r i g g e r f i s h e s ; a l l t h r e e fed mainly on a lgae . Furthermore, i n some of t h e dredged a r e a s t h i c k a l g a l mats developed over t h e whole bottom, with the blue- green a lgae Lyngbya majescula being t h e dominant spec ies . From these d a t a , Brock, e t a l . (1966) suggested t h a t a new cycle i n t h e product ion of c i g u a t e r i c f i s h e s a t Johnston may be i n an i n i t i a l s tage . These da ta a l s o support anda all's 1958 hypothesis discussed e a r l i e r f o r indeed following dredging (1) t h e blue-green a lgae increased , (2) t h e number of t o x i c herbivorous f i s h spec ie s increased , and (3) t h e number of c igua te ra poisonings increased . Published Johnston A t o l l t ox in d a t a from 1966 through 1973 has been very l i m i t e d , but does suggest t h a t l i t t l e change i n t o x i c i t y l e v e l s has occurred. Brock (1972) found t h a t c igua te ra tox in i n t h e moray e e l Gymnothorax javanicus has not s t a t i s t i c a l l y changed i n l e v e l from 1963 to 1970; t h e s e da ta a r e presented i n a l a t e r s e c t i o n . It i s not known whether seab i rds a r e a f f ec t ed by c iguatera poisoning; however, Halstead and Bunker (1954b) discovered t h a t experimental chickens a r e apparent ly unaffected by t h e l e s s v i r u l e n t f i s h poisons. Most seabi rds a t Johnston and elsewhere i n t h e c e n t r a l P a c i f i c , moreover, do not feed on inshore lagoon f i s h e s . A t Johnston, only Brown Boobies have been observed feeding i n t h e lagoon and t h i s spec ie s , White Terns, and Black Noddies normally feed o f f shore near the a t o l l ; t h e remaining spec ies usua l ly feed well a t sea (King, 1967). Table 16. Toxic i ty of f i s h spec ie s t e s t ed f o r c igua te ra a t Johnston A t o l l Halstead and Bunker, 1954 Brock, e t aZ., 1965 Brock, e t a l . , 1966* No. No. % No. No. % No. No. % Tested Toxic Toxic Tested Toxic Toxic Tested Toxic Toxic Triaenodon obesus Carcharhinus menisor~ah Aetobatus narinari Gymnothorax buroensis Gymnothorax javanicus Gymnothorax meleagris Be Zone p Zatyura AuZostomus chinensis Holocentrus Zacteoguttatus Holocentrus s m a r a Holocentrus sp in i fer Myriprist is argyromus Myriprist is b e m d t i Apogon menesemus Priacanthus cruentatus Table 16. (continued) Halstead and Bunker, 1954 Brock, e t aZ. , 1965 Brock, e t a z . , 1966 No. No. % No. No. % No. NO. 7 ," Tested Toxic Toxic Tested Toxic Toxic Tested Toxic Toxic Kyphosus bigibbus MoZZoielicktkys aur i f l ama i~uZZoidicktkys samoensis Parupeneus bi fasciatus Parupeneus chryserydros Parupeneus crassiZabris Pawpeneus t r i f a sc ia tu s Carangoides ferdau Caranx Zugubris Caram rnelampygus Abudefduf sordidus DascyZZus aZbiseZZa Dascy ZZus marginatus PZectrogZypkidodon johnstonianus CheiZinus rhodochrous EpibuZus ins id ia tor Table 16. (continued) Halstead and Bunker, 1954 Brock, e t aZ., 1965 Brock, e t aZ., 1966 NO. No. % N O . No. % No. No. % Tested Toxic Toxic Tested Toxic Toxic Tested Toxic Toxic ThaZassoma duperreyi 1 1 100.0 Scarus cyanogranunus Scarus dubius Scarus duperreyi Scarus fors ter i Chaetodon auriga Chaetodon citrineZZus Chaetodon ephippim Chaetodon rnuZticinctus Chaetodon ornatissimus Megaprotodon striganguZus ZancZus cornutus Acanthurus achiZZes Acanthurus nigroris Table 16. (continued) Halstead and Bunker, 1954 Brock, e t aZ., 1965 Brock, e t az . , 1966 No. No. % NO. No. % No. No. % Tested Toxic Toxic Tested Toxic Toxic Tested Toxic Toxic Acanthurus oZivaceus 6 2 33.3 Aeanthurus sandvieensis 5 2 40.0 16 0 0 Ctenochaetus hawaiiensis 2 0 0 Ctewchaetus s tr iatus 7 5 71.4 Ctenochaetus strigosus 5 0 0 iVaso Zituratus Zebrasoma fZavescens Botus mancus i14e Zichthys buniva iVeZichthys ringens Metichtkys vidua Rhinecanthus aculeatus Amanses caroZae Amanses sandwickiensis Kentrocarpus hexagonus Ostracion cubicus Table 16. (continued) Halstead and Bunker, 1954 Brock, et az., 1965 Brock, et al., 1966 No. No. % No. No. % No. No. % Tested Toxic Toxic Tested Toxic Toxic Tested Toxic Toxic Ostracion meleagris 9 9 100.0 Arothron meleagris Canthigaster jactator Number of Specimens Number of Species *Thirty-two other spec ie s i n a d d i t i o n t o t h e s i x l i s t e d were t e s t e d f o r t ox in ; a l l were negat ive but t h e i r names were not given. Species Accounts Although t h e f i s h fauna of Johnston A t o l l is we l l known, very l i t t l e i s known about t h e biology of i nd iv idua l spec ies occurr ing the re . Only one spec ie s , a moray e e l , and one family have been s tudied extens ive ly . MORAY EEL Gymnothorax javanicus S t a t u s Abundant breeding spec ie s ; p re sen t year-round throughout t h e lagoon and reef waters . Breeds during t h e summer months. Highest of a l l f i s h e s tox ic t o man a t Johnston; up t o 80 percent a r e t o x i c . Ecological D i s t r i b u t i o n Halstead and Bunker (1954a) f i r s t co l l ec t ed two specimens of Gzjmnothorm javanicus from Johnston A t o l l i n 1951. Addi t ional obser- v a t i o n s and c o l l e c t i o n s were repor ted by Brock, e t aZ. (1965, 1966) during 1963 through 1965. Brock (1972) found i t t o be very abundant from 1963 t o 1971. I n a l l , 1,165 specimens were taken a t Johnston by t h e Marine Toxins Program of t h e Hawaii I n s t i t u t e of Marine Biology, Univers i ty of Hawaii. This spec ie s is a c o r a l reef dwe l l e r , i s very c r y p t i c i n c o l o r , and h ides i n reef c revices . A t Johnston, i t has been found throughout t h e lagoon and reef waters . It has been found under rubble i n ex tens ive ly dredged a r e a s , but i s more commonly encountered i n a r e a s of dense c o r a l growth. I ts v e r t i c a l range i s unknown, but has been co l l ec t ed a t Johnston a t depths ranging from 0.3 t o 17 meters. Populat ions Although Brock, e t aZ. (1965, 1966) found G. javanicus r a r e i n t h e i r s t u d i e s , Brock (1972) found f a i r numbers (6 t o 164, mean = 50) i n a sample of 648 e e l s co l l ec t ed a t 1 3 s t a t i o n s throughout t h e lagoon. Addi t ional populat ion e s t ima tes or s t u d i e s a r e lacking. Th i s species--perhaps t h e l a r g e s t of the Indo-Pacific morays-- probably l i v e s t o be older than 20 yea r s . The only e e l predators of s ign i f i cance a t Johnston appear t o be sharks (Brock, 1972). Annual Cycle Gymnothorax javanicus occurs a t Johnston A t o l l throughout t h e year , a l though breeding occurs only i n June, Ju ly , and August. Females re - l e a s e about 188,000 t o 291,000 eggs per spawning. Males mature a t 3.4 kg and females a t 4.6 kg i n weight. Males, however, a t t a i n a l a r g e r s i z e than Eemaleg. This spec ie s feeds c h i e f l y c repuscular ly and noc tu rna l ly ; however, attempted d iu rna l feeding has been observed. The v a r i e t y of food items i n d i c a t e s i t i s an oppor tun i s t i c predator ; 89 percent cons is ted of f i s h e s . Gut content a n a l y s i s revea led , however, t h a t t h i s spec ie s f eeds in f r equen t ly (Brock, 1972). Ciguatera Halstead and Bunker (1954a) f i r s t documented c igua te ra a t Johnston i n 1950 and noted t h a t t ox in occurred i n one of two Gymnothorux javanicus specimens examined. Brock (1972) examined 887 e e l s of t h i s spec ie s taken a t Johnston and found no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s between t h e l e v e l s of t o x i c i t y from 1963 through 1970. Analysis of t h e d i s t r i b u t i o n of t o x i c i t y showed no s i g n i f i c a n t d i f f e r e n c e s i n t h e l e v e l s of t o x i c i t y among t h e 14 h a b i t a t a r e a s ; however, t h e r e was a s i g n i f i c a n t c o r r e l a t i o n of t o x i c i t y wi th depth. This f u r t h e r suggests t h a t t h e r e is more tox in i n t h e food of G . javanicus a t depths of 6 t o 1 2 m e t e r s , compared t o depths of 0 t o 6 meters . This spec ie s a l s o displayed a s i g n i f i c a n t i nc rease i n t o x i c i t y wi th increas ing body s i z e . No s i g n i f i c a n t d i f f e r e n c e i n t h e t o x i c i t y of t h e f l e s h from males and females ex i s t ed , however. Up t o 80 percent of a l l specimens examined were t o x i c (Brock, 1972). Movement Mark and recapture methods, a s wel l a s i n d i r e c t observa t ions , suggested t h a t on a short-term b a s i s ( l e s s than one year) Gymnothorm javanicus has a d e f i n i t e home range and its migrat ion i s r e s t r i c t e d (Brock, 1972). SURGEONFISHES Acanthuridae Jones (1968) s tudied eco log ica l r e l a t i o n s h i p s between 13 spec ie s of surgeonfishes, family Acanthuridae, found on Johnston A t o l l i n an attempt t o determine hab i t a t s epa ra t ion and feeding h a b i t s . He concluded t h a t although t h e r e appeared t o be unl imited food a v a i l a b l e f o r a l l spec ie s , t h e f i s h e s were separable on eco log ica l grounds. He recognized four spec ie s groups by hab i t a t (mid-water, sand pa tch , subsurge r e e f , and surge zones); t h r e e d i f f e r e n t ways of feeding (zooplankton f eede r s , g raze r s , and browsers); and a t l e a s t four d i f - f e r e n t c a t e g o r i e s of foods ea t en (zooplankton, i n t e r s t i t i a l m a t e r i a l , coarse a lgae , and filamentous a l g a e ) . He a l s o described numerous modif ica t ions of t h e al imentary cana l which suggested i n t e r s p e c i f i c d i f f e r e n c e s i n food handling. He hypothesized t h a t t h e r e must be in- f requent per iods of food shortage during which s e l e c t i o n pressure was high enough t o favor adap ta t ions t h a t would tend t o reduce i n t e r s p e c i f i c competition. R e p t i l e s Two r e p t i l e species--"one long brown spec ie s and one shor t e r grey species1'--were recorded by E.H. Bryan, Jr . (ms.) i n Ju ly 1923 when t h e f i r s t s c i e n t i f i c v i s i t was made t o Johnston Ato l l . He indicated t h a t t hese were then abundant. Five spec ie s of r e p t i l e s a r e now lcnown from t h e A t o l l . A l l but one spec ies , t h e Black Sea T u r t l e , were probably introduced by man. They a r e a l l known from va r ious i s l ands throughout t h e c e n t r a l P a c i f i c . Of t h e f i v e spec ie s , two spec ie s occur only on Johnston Is land and two spec ie s occur on Sand Is land . Only one spec ie s occurs on both i s l ands . A s of 1969, none was known from Akau and Hikina Is lands . Species Accounts There a r e no genera l re ferences t h a t i l l u s t r a t e t h e r e p t i l e s of Johnston Ato l l . Taxonomy of t h e t u r t l e s fo l lows Carr (1972) and Arnerson (1971). Order of l i s t i n g f o r l i z a r d s fol lows Brown (1957). BLACK SEA TURTLE CheZonia agassiz i Sta tus Regular uncommon v i s i t o r ; known from t h e lagoon, of fshore Johnston I s l and , and Sand I s l and . Observations Brooke (ms.), who v i s i t e d Johnston A t o l l i n March 1859, commented about t h e l a c k of t u r t l e s : "The r e e f s a r e covered with f i s h of va r ious kinds. Mullet abound, but t h e r e a r e no t u r t l e s . " Wetmore (ms. a and b ) , l ikewise , recorded no t u r t l e s a t Johnston A t o l l i n Ju ly 1923. POBSP personnel recorded sea t u r t l e s i n t h e shallow marginal reef a rea west of Johnston I s l and i n J u l y 1963. An a d u l t (USNM 163581) was co l l ec t ed 20 November 1966 on t h e beach of Sand I s l and . I s land personnel i n 1973 repor ted seeing 10 t o 12 t u r t l e s of fshore of Johnston I s l and throughout t h e year . A longtime r e s i d e n t estimated harves t ing 12 t o 15 per year . Annual Cycle The Black Sea T u r t l e apparent ly v i s i t s Johnston A t o l l year-round. No records e x i s t of i t breeding on t h e a t o l l , a l though perhaps i t d i d i n small numbers p r i o r t o inhab i t a t ion by man. This spec ie s breeds during t h e summer i n t h e northwestern Hawaiian I s l ands , e s p e c i a l l y a t French F r i g a t e Shoals (Arnerson', 1971). HOUSE GECKO HemidactyZus fienatus S t a t u s Common introduced breeder; occurs only on Sand I s l and . Observations It i s not known when House Geclcos were introduced t o Johnston A t o l l . POBSP personnel c o l l e c t e d two specimens from Sand Is land i n May 1964 (USNM 154207-208) and two more i n May and March 1966 (USNM 163579-580). FOX GECKO Hemidactylus garnotii S t a t u s Uncommon introduced breeder; occurs on Johnston and Sand Is lands . Observations POBSP personnel co l l ec t ed a Fox Gecko from Johnston Is land 2 J u l y 1966 (USNM 166825). Another was co l l ec t ed a t Sand Is land 22 August 1968 (USNM 166863). MOURNING GECKO LepidodactyZus Zugubris Sta tus Uncommon introduced breeder; occurs only on Johnston Is land . Observations A Mourning Gecko was co l l ec t ed (USNM 156990) from Johnston Is land 28 October 1964 by POBSP personnel . SNAKE-EYED SKINK AbZepharus boutonii poec i~op~eurus S t a t u s Uncommon introduced breeder; occurs only on Johnston I s l and ; present s t a t u s unknown. Observations Thi r teen specimens of t h i s spec ies were co l l ec t ed by E.H. Bryan, Jr . , on Johnston I s l and i n J u l y 1923 (USNM 66810-22). None has been recorded s ince . Birds Several sources were used i n assembling t h e common and s c i e n t i f i c names of t h e b i r d s occurr ing a t Johnston A t o l l (Table 17 ) . The names used i n t h e American ~ r n i t h o l o g i s t s ' Union's Check-List of North American Birds (1957), a s amended by Eisenmann, e t a t . (1973), were followed f o r s p e c i e s occurr ing i n North America. I n t h e i n t e r e s t of cons is tency , s eab i rd names agree with those which appear i n Watson's Smithsonian Iden t i f i ca t ion Manual: Seabirds of the Tropical At lant ic Ocean, and King's Smithsonian Iden t i f i ca t ion Manual: Seabirds of the Tropical Paci f ic Ocean. Taxonomic order fo l lows t h a t of P e t e r ' s Check-List of Birds of the WorZd, volumes I , 11, and 111, with t h e exception of t h e P roce l l a r i i fo rmes , which fo l low Alexander, e t a l . (19651, t h e Anseriformes, which fol low Delacour (1954, 1959), and t h e Charadri i - formes, which fol low Bock (1958) and J e h l (1968). Table 17. Birds from Johnston Atol lk* Order P roce l l a r i i fo rmes Family Diomedeidae Diomedea nigripes* Diomedea inrmutabiZis* Family P r o c e l l a r i i d a e Pterodroma alba* Bu Zweria bu Zwerii Puffinus pacif icus Puffinus n a t i v i t a t i s Puffinus puffinus neweZZi" Family Hydrobatidae Oceanodroma tristrami* Order Pelecaniformes Family Phaethontidae Phaethon aethereus" Phaethon rubricauda Phaethon tepturzrs" Family Sulidae SuZa dacty latra* SuZa Zeucogaster SuZa suZa Family Fregat idae Fregata minor Fregata ariez* Order Ciconiiformes Family Ardeidae BztbuZcus i b i s* Order Anseriformes Family Anatidae Anas acuta* Anas [=Mareca] americana* Anas [=Spatula] cZypeata* Black-footed Albat ross Laysan Albat ross Phoenix P e t r e l Bulwer's P e t r e l Wedge-tailed Shearwater Christmas Shearwater Newell 's Shearwater Sooty Storm Pe t r e l Red-billed Tropicbird Red-tailed Tropicbird White-tailed Tropicbird Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd Lesser F r iga teb i rd C a t t l e Egret P i n t a i l American Wigeon Northern Shoveler T a b l e 1 7 . ( con t inued) Order G a l l i f o r m e s Family P h a s i a n i d a e GaZZus gaZZus Order F a l c o n i f ormes Family F a l c o n i d a e FaZco peregrinus tundrius* Order C h a r a d r i i f o r m e s Family C h a r a d r i i d a e PZuviaZis dominica" PZuviaZis [=SquataroZa] squataroZa4 Charadrius semipatmatus* Family Sco lopac idae Nwnenius tah i t i ens i s* Tringa [ =Totanus] f k v i p e s * A c t i t i s macuZaria* Catoptrophorus semipaZmatus* HeterosceZus incanus [=ineanwn]* Arenaria interpres* Limnodromus sp." CaZidris [=Crocethia] aZba* CaZidris [=Ereunetes] mauri* CaZidris [=EToZia] melanotos* CaZidris [=EroZia] acminataX Tryngites subruficoZZis* Phi Zomachus pugnax * Family Pha la ropod idae Steganopus tr icolor* Family L a r i d a e Lams gZaucescens* Lams argentatus" Larus atriciZZaX Larus pipixcan* Larus spp .* Sterna Zunata Sterna fuscata ThaZasseus eZegans* Proeelsterna ceruZea* Anous s tol idus Anous tenu iros t r i s Gygis atba Order Columbiformes Family Columbidae CoZwnba Zivia Domestic Chicken P e r e g r i n e F a l c o n American Golden P l o v e r B lack-be l l i ed P l o v e r Semipalmated P l o v e r B r i s t l e - t h i g h e d Curlew L e s s e r Ye l lowlegs Spo t t ed Sandpiper Willet Wandering T a t t l e r Ruddy Turns tone Dowitcher s p e c i e s Sander l i n g Western Sandpiper P e c t o r a l Sandpiper Sharp- ta i l ed Sandpiper Buf ? -b reas ted Sandpiper Ruff W i l s o n ' s P h a l a r o p e Glaucous-winged G u l l Her r ing G u l l Laughing G u l l F r a n k l i n ' s G u l l G u l l s p e c i e s Gray-backed Tern Sooty Tern E l e g a n t Tern Blue-gray Noddy Brown Noddy Black Noddy White Tern Rock Dove Order S t r i g i f o m e s Family S t r i g i d a e Asio fZanoneus* Short -eared Owl Table 1 7 . (continued) Order Passeriformes Family Alaudae AZauda arvensis* Family Zosteropidae Zosterops japonica* Family E s t r i l d i d a e Lonchura s t r i a t a Skylark Japanese White-eye Society Finch **Resident b i r d s a r e unmarked; non-resident b i r d s a r e marked wi th an * In t roduc t ion The 56 b i r d spec ie s recorded belong t o 10 o rde r s , 19 f ami l i e s , and 38 genera; 22 spec ie s a r e c l a s s e s a s seab i rds , and 34 spec ies a r e waterfowl, marsh, and land b i r d s (Table 18 ) . Table 18. S ta tus of b i r d s on Johnston Ato l l Sand Akau Hikina Johnston Or ig ina l Man-made Seabirds: Breeders ~ u l w e r ' s P e t r e l Wedge-tailed Shearwater Christmas Shearwater Red-tailed Tropicbird Brown Booby Red-f oo ted Booby Great Fr i ga t eb i rd Gray-backed Tern Sooty Tern Brown Noddy Black Noddy White Tern Former Breeders Black-footed Albat ross Laysan Albat ross Blue-faced Booby V i s i t o r s Phoenix P e t r e l Newell's Shearwater Sooty Storm P e t r e l Red-billed Tropicbird White-tailed Tropicbird 0 Lesser Fr i g a t e b i r d Blue-gray Noddy Table 18. (continued) Sand Or ig ina l Man-made Akau Hikina Johnston Waterfowl, Marsh, and Land Birds: Regular Migrants P i n t a i l American Golden Plover R R Br is t le - th ighed Curlew R Wandering T a t t l e r R R Ruddy Turnstone R R Sander l i n g pec to ra l Sandpiper I r r e g u l a r V i s i t o r s American Wigeon Northern Shoveler Glaucous-winged Gull Herring Gull Laughing Gull Short-eared O w l S t r agg le r s C a t t l e Egret ~ r a n k l i n ' s Gull Accidentals Peregr ine Falcon lack-bellied Plover Semipalmated Plover Lesser Yellorvlegs Spotted Sandpiper Wil le t Dowitcher spec ie s Western Sandpiper Sharp-tailed Sandpiper Buff-breasted Sanduiuer . . Ruff Wilson's Phalarope Gull spec ie s Elegant Tern Skvlark Japanese White-eye In t roduct ions Domestic Chicken Rock Dove Society Finch Present Breeders L* 2"" Former Breeders 0 0 Tota l spec ie s 8 6 B = Breeder; R = Recorded; 0 = Over f l i e r . Cap i t a l l e t t e r s i n d i c a t e s t a t u s 1963-1969; lower case l e t t e r s i n d i c a t e s t a t u s 1923-1962, i f d i f f e r e n t than a t p re sen t . * bred only i n 1964 ** bred only i n 1973. Seabirds Of the 22 seabi rd spec ie s recorded a t Johnston A t o l l , 12 a r e breeders , t h r e e a r e former breeders , and seven a r e v i s i t o r s (Table 18) Breeders: A l l 12 r e s i d e n t breeding spec ies nes t i n t h e Hawaiian I s l a n d s and o ther p a r t s of t h e t r o p i c a l P a c i f i c . These 12 appear t o have c lose r a f f i n i t i e s wi th t h e i r r e s p e c t i v e northwestern Hawaiian populat ions than with those i n the Line and Phoenix I s l ands . See a l s o t h e Banding and Movement sec t ion . Former Breeders: Three spec ie s formerly bred a t Johnston Ato l l . The Black-footed Albat ross p re sen t ly breeds only i n t h e Hawaiian I s l ands and t h e Bonin-Volcano I s l a n d s a r e a , whi le t h e Laysan Albat ross p re sen t ly breeds exc lus ive ly i n t h e Hawaiian I s l ands . Both spec ie s normally range nor th of 10?N. The Blue-faced Booby breeds throughout t h e t r o p i c a l P a c i f i c . V i s i t o r s : I n t h e surrounding ocean one may f i n d both seabi rd spec ie s t h a t use or breed a t Johnston A t o l l and those t h a t seldom occur t h e r e . These l a t t e r spec ie s (Table 18) inc lude both breeders from t h e Hawaiian I s l ands and Line-Phoenix I s l ands , a s we l l a s breeders from other a r e a s of t h e P a c i f i c who migrate i n t o o r through t h e surrounding waters during t h e i r non-breeding season (POBSP, 1967a). Normally most of these 28 b i r d spec ie s s t a y a t sea , b u t , because of s ickness or bad weather, any could a l i g h t on t h e i s l a n d s a t Johnston A t o l l . The seven seabi rd v i s i t o r s t o Johnston A t o l l come from t h e no r th , south , and e a s t P a c i f i c . The Newell's Shearwater breeds exc lus ive ly i n t h e main Hawaiian I s l ands , while t h e Sooty Storm P e t r e l breeds only i n t h e Hawaiian I s l a n d s and the Bonin-Volcano I s l ands a rea . Although t h e White-tailed Tropicbi rd and Blue-gray Noddy breed throughout t h e t r o p i c a l P a c i f i c , those tha t v i s i t Johnston a r e thought t o breed pr imar i ly i n t h e Hawaiian :Eslands. V i s i t o r s eab i rds from t h e south P a c i f i c a r e the Phoenix P e t r e l and Lesser F r iga teb i rd . Both a r e e q u a t o r i a l , south-cent ra l P a c i f i c breeders . The Lesser F r iga teb i rd has been recorded from t h e western P a c i f i c , Wake, and Kure, and may have a clockwise migrat ion p a t t e r n t h a t occas ional ly inc ludes Johnston on t h e r e t u r n t o t h e i r southern P a c i f i c breeding i s l ands . From t h e e a s t P a c i f i c comes t h e Red-billed Tropicbird which breeds on i s l a n d s along t h e coas t of Cent ra l and South America. Waterfowl, Marsh, and Land Birds The 34 spec ie s of waterfowl, marsh, and land b i r d s recorded a t Johnston A t o l l (Table 18) a r e he re in divided i n t o regular migrants (seven s p e c i e s ) , i r r e g u l a r v i s i t o r s ( s i x s p e c i e s ) , s t r a g g l e r s (two s p e c i e s ) , acc iden ta l s (16 s p e c i e s ) , and in t roduc t ions ( t h r e e spec ie s ) . Regular Migrants: One of t h e r egu la r migrants i s t h e P i n t a i l which breeds i n temperate North America, Europe, and Asia. The re- maining s i x spec ie s a r e shore b i r d s which a r e a l l a r c t i c breeders . Of t h e seven spec ie s , three-- the P i n t a i l , Br is t le - th ighed Curlew, P e c t o r a l Sandpiper, and Sanderling--are r e g u l a r , but uncommon. The remainder a r e common. These r egu la r migrant shorebi rds breed during t h e summer i n t h e Northern Hemisphere and migrate south f o r t h e winter . Some use Johnston A t o l l a s a "wintering ground"; o t h e r s , p a r t i c u l a r l y f i r s t - year b i r d s , spend t h e summer here. I r r e g u l a r V i s i t o r s : Whereas r egu la r migrants have a s e t p a t t e r n t o t h e i r movements, t h e s i x i r r e g u l a r v i s i t o r s have no s e t p a t t e r n i n t h e i r v i s i t s t o Johnston. This group con ta ins two ducks, both temperate breeders ; t h r e e g u l l s , a l l s u b a r c t i c and temperate breeders ; and an owl, which breeds i n t h e nor th-cent ra l P a c i f i c and va r ious temperate a reas . S t r agg le r s : The two spec ie s i n t h i s group r a r e l y v i s i t Johnston, but t h e a t o l l i s wi th in t h e i r range. The F rank l in ' s Gull. breeds i n northwestern North America, and t h e C a t t l e Egret has i t s c l o s e s t breeding populat ion i n t h e main Hawaiian I s l ands . Accidentals : The acc iden ta l spec ie s a t Johnston a r e so c l a s s i f i e d because they a r e out of t h e i r normal range of occurrence. Fourteen spec ie s a r e a r c t i c and temperate breeders . Two land b i rd spec ie s a r e introduced nor th-cent ra l P a c i f i c breeders . The rain-water puddles on Johnston may a t t r a c t acc iden ta l b i r d s , e s p e c i a l l y shorebirds. In t roduct ions : Three spec ie s of b i r d s have been introduced by man. The Rock Dove breeds and t h e Domestic Chicken probably breeds; both s p e c i e s a r e semi-tame. The Socie ty Finch i s caged. Annual Cycles Among t h e b i r d spec ie s a t Johnston A t o l l , annual. breeding and popula t ion cyc les vary. Breeding Cycles: The seab i rds breed during a l l seasons of t h e year (Fig. 3 7 ) . Most have s h o r t , d i s t i n c t breeding periods; some have extended breeding cycles . Based on peak breeding per iods , t h e 12 present breeding seabi rd spec ies a r e grouped a s follows (Table 19 ) : winter and spr ing breeders (one s p e c i e s ) , spr ing and summer breeders (n ine s p e c i e s ) , summer breeders (one s p e c i e s ) , summer and f a l l breeders (one spec ie s ) ; none i s a f a l l and winter breeder. Two former breeding spec ie s were probably winter and spr ing breeders; another was most l i k e l y a spr ing and summer breeder . Table 19. Peak breeding period of Johnston A t o l l b i rds Winter-Spring Spr ing-Summer Summer Summer-Fall Gray-backed Tern Christmas Shearwater Bulwer's P e t r e l Wedge-tailed Red-tailed Tropicbird Shearwater Brown Booby Red-footed Booby Great F r iga teb i rd Sooty Tern Brown Noddy Black Noddy White Tern Winter and Spring: The s i n g l e winter and spr ing breeder is t h e Gray-backed Tern. I n t h e northwestern Hawaiian I s l ands , where space and n e s t s i t e competi t ion i s no problem, t h i s spec ies i s a spr ing and summer breeder . Apparently because of n e s t s i t e competition wi th Sooty Terns on t h e reduced space a v a i l a b l e a t Sand I s l and , t h e Gray-backed Terns have s h i f t e d t h e i r nes t ing cyc le so t h a t f i r s t eggs a r e l a i d by e a r l y or mid-winter. Last chicks f l e d g e by l a t e summer. The two former breeders , Black-footed Albat ross and Laysan Albat ross , were probably winter and spr ing breeders . Spring and Summer: Of t h e n ine spec ie s with a spr ing and summer peak breeding per iod , one i s a p roce l l a r i i fo rm, four a r e pelecaniforms, and four a r e charadri i forms. Egg l ay ing and f ledging wi th in t h i s group v a r i e s . Only two spec ies a c t u a l l y s t a r t laying eggs during t h e spr ing months: Christmas Shearwater and Black Noddy. Indiv idual b i r d s of t h e remaining seven spec ies commence lay ing during t h e winter months-- t h e Brown Noddy a s e a r l y a s December, t h e Red-tailed Tropicbi rd , Brown Booby, Great F r iga teb i rd i n January, and t h e Red-footed Booby, Sooty Tern, and White Tern i n February. Of t h e n ine spring-summer breeders , only t h e young of two spec ies (Black Noddy and White ern) completely f l edge by t h e end of t h e summer months. The young o f t w o spec ie s (Christmas Shearwater and Sooty Tern) normally commence f ledging i n t h e summer and extend i n t o e a r l y f a l l . The Brown Noddy extends i ts f ledging period t o l a t e f a l l . Fledging of t h e remaining four spec ie s (Red-tailed Tropicbi rd , Brown Booby, Red-footed Booby, and Great F r iga teb i rd ) extends i n t o e a r l y winter . The Blue-faced Booby, a former breeder , probably had a sp r ing and summer peak breeding season. Bulwer's Petrel Wedge-tailed Shearwater Red-tailed Tropicbird Great Frigatebird e . J i i i i I I Brown Booby Red-footed Booby Gray-backed Tern *a 8 8 8 . e e 0 Black Noddy eeem aeeeee maaeee . . . . . . . . . . . . . . . . White Tet.i i J F A M J J A S O N D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 3 7 . Breeding cyc le s of s eab i rds a t Johnston Atol l ; s t i p p l e d a rea r e p r e s e n t s eggs, barred a rea young, and b lack d o t s non-breeding b i r d s . eee Summer: Only one spec ie s , Bulwer's P e t r e l , a p r o c e l l a r i i d , has a peak breeding. season t h a t i s contained i n a s i n g l e three-month period. Actual ly t h i s spec ie s could be considered a s a spr ing and summer breeder s i n c e cour t sh ip begins i n l a t e March and f i r s t eggs a r e l a i d t h e l a s t of May. O r i t could be considered a summer and f a l l breeder because a few f l e d g l i n g s do not leave u n t i l e a r l y September. The cyc le of t h i s spec ie s i n t h e northwestern Hawaiian I s l a n d s is i n f a c t s l i g h t l y l a t e r and is t h e r e considered t o be a summer and f a l l breeder . Summer and F a l l : The Wedge-tailed Shearwater, a p roce l l a r i i fo rm, i s t h e only spec ie s a t Johnston A t o l l t h a t has a summer and f a l l peak breeding period. Eggs a r e l a i d i n e a r l y June and young f l edge by l a t e f a l l or e a r l y winter . Extended: Although a l l 12 breeding spec ies have a peak breeding per iod , f i v e spec ie s a r e considered t o have an extended breeding season. These a r e t h e Red-tailed Tropicbi rd , Brown Booby, Red-footed Booby, Great F r i g a t e b i r d , and Brown Noddy. I n a l l of t hese spec ie s , t h e egg lay ing period and f ledging period each extend a t l e a s t over a three-season span. Populat ion Cycles: Many of t h e b i r d spec ies using Johnston A t o l l l eave t h e A t o l l during p a r t of each year ; o the r s s t a y throughout t h e year (Fig. 37 and Table 20). Even so , a l l have a populat ion buildup sometime during t h e year. Breeding Seabirds: Although t h e breeding populat ion c o n s i s t s of 12 spec ie s , f i v e spec ie s a r e dominant both i n t o t a l numbers and i n t h e i r importance t o t h e surrounding ocean (Fig. 38). The Sooty Tern, w i th a mean populat ion of 300,000 t o 310,000 breeding b i r d s i n March, A p r i l and May, makes up 95 percent or more of t h e t o t a l i s l a n d populat ion between February and Ju ly ; perhaps a s many a s 600,000 Sooty Terns use Johnston A t o l l annual ly . Red-footed Boobies, whose mean populat ion ranges up t o 3,750 b i r d s , ranks second i n seabi rd numbers i n winter and spr ing; most of t h e s e b i r d s a r e t r a n s i e n t s f o r only a few young a r e produced each year . The Brown Noddy ranks t h i r d i n mean populat ion numbers, but ranlcs second i n number of young (about 1,000) produced each year . The Wedge-tailed Shearwater ranks f o u r t h i n numbers of a d u l t s us ing t h e a t o l l and is present only from March t o e a r l y December; i t ranks t h i r d i n numbers of young (up t o 250) produced annual ly. The Great F r iga teb i rd ranks f i f t h i n populat ion numbers (a mean peak of 750 i n March and A p r i l ) , bu t only produces about 130 f l e d g l i n g s year ly . Mean monthly populat ions f o r a l l t h e o t h e r spec ie s , combined, never t o t a l s more than 600, nor lower than 300. A s is evident from Figure 38 , b i r d populat ion numbers a r e extremely high (up t o 310,000) from mid-winter through summer. Th i s co inc ides wi th t h e peak breeding per iods . During t h e f a l l and e a r l y winter t h e t o t a l populat ion usua l ly is below 9,000 b i r d s . Table 20. Monthly occurrence of non-resident b i r d s a t Johnston A t o l l Species Black-footed Albat ross Laysan Albat ross Phoenix P e t r e l ~ e w e l l ' s Shearwater Sooty Storm P e t r e l Red-billed Tropicbird White-tailed Tropicbird Blue-faced Booby Lesser F r iga teb i rd C a t t l e Egret P i n t a i l American Wigeon Northern Shoveler Peregr ine Falcon American Golden Plover Black-bellied Plover Semipalmated Plover Br is t le - th ighed Curlew Lesser Yellowlegs Spotted Sandpiper W i l l e t Wandering T a t t l e r Ruddy Turnstone Dowitcher sp. Sanderl ing Western Sandpiper P e c t o r a l Sandpiper Sharp-tai led Sandpiper Buff-breasted Sandpiper Ruff Wilson's Phalarope Glaucous-winged Gull Herring Gull Laughing Gul l Frankl in ' s Gull Gull sp. Elegant Tern Blue-gray Noddy Short-eared O w l Skyiark Japanese White-eye Jan Feb Mar Apr May Jun J u l Aug Sep Oct Nov Dec X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X * * * * * X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X *In c a p t i v i t y . 0 Sooty Tern D Red-footed Booby Brown Noddy l.jedge-tailed Shearwater G r e a t F r i g a t e b i r d O the r s J F M A M J J A S O D Figure 38. Monthly cummulative bird populations, Johnston Atoll 1963-1969. Of t h e 12 breeding spec ie s , seven a r e present on t h e a t o l l through- out t h e year (Fig. 37). The remaining f i v e spec ie s spend from 1 112 months t o s i x months away from Johnston. Most of these probably leave t h e c e n t r a l P a c i f i c and migra te t o d i s t a n t a reas . Former Breeding Seabirds: The Blue-faced Booby i s p resen t , though uncommon, throughout t h e year (Table 20). Black-footed Albatross have been recorded on Johnston A t o l l i n November, and March, while Laysan Albat ross have been observed during November, December, and Ju ly ; both a l b a t r o s s e s may occur o f f shore during l a t e winter and e a r l y spr ing . Regular Migrants: Of t h e seven regular migrants , three--American Golden Plover , Wandering T a t t l e r , and Ruddy Turnstone--are known i n a l l months (Fig. 39 and Table 20). Although the Wandering T a t t l e r and Sanderl ing a r e found i n low numbers throughout t h e yea r , American Golden Plovers and Ruddy Turnstones show peak populat ion per iods i n f a l l and mid-winter and e a r l y sp r ing ; t h e s e peaks correspond to n ~ i g r a t i o n s from A r c t i c breeding a r e a s i n f a l l and migrat ions no r th i n mid-winter and e a r l y spr ing . A s l i g h t populat ion dec l ine occurs i n e a r l y winter ; lowest populat ions occur during t h e summer months when only immatures remain on t h e a t o l l . The Br is t le - th ighea Curlew is known from a l l months except Ju ly . The P i n t a i l has been observed i n most years from September through March; c a p t i v e b i r d s have been kept from Apr i l through August. The Pec to ra l Sandpiper has been recorded i n most years i n A p r i l and May and i n September, October and November. I r r e g u l a r V i s i t o r s , S t r agg le r s , and Accidental Birds: The monthly occurrence of t h e i r r e g u l a r v i s i t o r s , s t r a g g l e r s , and a c c i d e n t a l spec ies i s presented i n Table 20. A s fo r t h e seven v i s i t i n g seab i rds , t h e White-tailed Tropicbird has been recorded from a l l months except f o r June, and October and November. The Red-billed Tropicbi rd , however, i s known only from A p r i l , May, and June. S imi l a r ly , t h e Blue-gray Noddy is known from Apr i l , May, and J u l y . The Lesser F r iga teb i rd has been recorded during March and August. The Newell 's Shearwater a l s o has only occurred during two months--June and August. The Phoenix P e t r e l and Sooty Storm P e t r e l have been seen only one month, r e spec t ive ly September and December. Of t h e s i x i r r e g u l a r g u l l v i s i t o r s , t h e Laughing Gull has been recorded from four months, t h e Herring Gull from t h r e e months, and Glaucous-winged Gull from two months. The American Wigeon and Northern Shoveler a r e each known from twomonths. The Short-eared O w l , however, has been observed i n a l l months except August, September, and October. One of t h e two s t r a g g l e r s , t h e C a t t l e Egre t , is known from a l l months except June and J u l y , while t h e o t h e r , t h e Franlclin's Gul l , i s known from only March. 10 *--e--* - -0--0 --? --? --e --e / H -2.- -- 0 J F M A M J J R S O N D Figure 39, Monthly mean shorebi rd popula t ions f o r Johnston A t o l l , 1963-1969; Golden Plover ( s o l i d l i n e ) , Ruddy Turnstone ( d o t s ) , Wandering T a t t l e r (dashes). Of t h e 15 acc iden ta l waterfowl, marsh, and land b i r d s , t h e Japanese White-eye i s known from f i v e months, t h e Black-bellied Plover from four months, t h e Semipalmated Plover and g u l l spec ie s from t h r e e months each, t h e Peregrine Falcon, Spotted Sandpiper, Dowitcher spec ie s and Sharp-tailed Sandpiper from two months each; t h e remain- ing e i g h t spec ie s a r e known from one month each. Introduced B i r d s : The t h r e e introduced b i r d spec ie s a r e known from a l l months. Furthermore, both breeding spec ie s probably breed year-round. At-Sea Birds: I n August 1963, a 50,000 square mi le , r ec t angu la r , pe l ag ic g r i d was e s t ab l i shed by t h e POBSP, centered approximately 175 mi l e s southwest of Johnston Ato l l . I n a l l , 42 monthly survey c r u i s e s were conducted i n t h i s g r i d through February 1967. Birds, pr imar i ly s e a b i r d s , were observed along 22,898 mi l e s of daytime t r a v e l and along 10,819 mi l e s of n igh t t r a v e l . Pe lagic observa t ions maintained f o r more than 2,500 hours i n daytime and more than 1,150 hour a t n igh t recorded 33,261 b i r d s of 4 1 spec ie s . Tables 21 and 22 show, respec t - i v e l y , monthly occurrences and a rea d e r i v a t i o n of t hese spec ies . F igure 40 p resen t s t h e monthly f l u c t u a t i o n i n t h e number of b i r d s wi th in t h i s g r i d . A d e f i n i t e 12-month d i u r n a l cyc le e x i s t s which has four b a s i c f e a t u r e s . There i s a populat ion low from l a t e December through e a r l y March and i s p r imar i ly a r e f l e c t i o n of t h e absence of Sooty Terns and Wedge- t a i l e d Shearwaters. The major elements of t h e avifauna a t t h i s time a r e probably Johnston A t o l l non-breeding spec ie s , although a t l e a s t one no r th P a c i f i c non-breeding spec ie s and two northwestern Hawaiian I s l ands breeding spec ie s r e g u l a r l y occur i n smal l numbers. A spr ing peak e x i s t s from l a t e March through e a r l y May and is p r imar i ly t h e r e s u l t of the a r r i v a l of Johnston A t o l l breeding spec ie s i n t h e a r e a . I n add i t ion , t h e number of b i r d s is augmented by t h e passage of migrants moving between d i s t a n t a r e a s , pr imar i ly from t h e south P a c i f i c t o t h e nor th P a c i f i c . There i s a summer p la teau from l a t e May through August. Johnston A t o l l breeding spec ie s predominate a t t h i s time. The numbers a r e , however, supplemented by so journers from t h e south P a c i f i c . The cycle shows a f a l l mj.gration pealc--higher even than t h e spr ing peak--from September through e a r l y December. Migrating seab i rds , moving from t h e no r th P a c i f i c t o t h e south P a c i f i c , make up t h e bulk of t h e pe lag ic populat ion a t t h i s time. Sooty Terns and Wedge-tailed Shear- waters , perhaps from t h e northwestern Hawaiian I s l ands and passing through on migra t ion , a l s o con t r ibu te t o t h e September peak. F igure 4 1 p re sen t s t h e monthly d i u r n a l populat ion f l u c t u a t i o n wi th in t h e g r i d by spec ie s group. Two groups, t h e shearwater-petrel group and t h e t e r n group, account f o r over 90 percent of a l l b i r d s present . The shearwater-petrel group accounts f o r 54 percent of a l l b i rds throughout t h e year ; i t i s t h e most abundant of a l l groups from July through December. The t e r n group comprises 39 percent of a l l b i r d s present throughout t h e year; i t i s t h e most abundant group from ?larch through June. The t rop icb i rd group accounts f o r two percent of a l l b i r d s present year-round. The booby group accounts f o r only one percent of a l l b i r d s present throughout t h e yea r , bu t i s t h e most abundant group from January through February. I n a l l , 21 seabi rd spec ie s were recorded during the nocturna l ob- se rva t ions . Because of t h e d i f f i c u l t y i n observing most spec ie s , only Sooty Terns were counted wi th any degree of accuracy. The nocturna l annual cyc le (Fig. 42) , t he re fo re , p r imar i ly r e f l e c t s the Sooty Tern cyc le r a t h e r than t h e t o t a l populat ion. Nevertheless , two populat ion peaks were prominent, one i n February, and another i n March. Table 21. Occurrence of b i r d s a t sea i n t h e g r id 175 mi les southwest of Johnston Atoll Species Black-footed Albat ross Laysan Albat ross Dark-rumped P e t r e l Juan Fernandez P e t r e l White-necked P e t r e l T a h i t i P e t r e l Phoenix P e t r e l Mottled P e t r e l Herald P e t r e l Kermadec P e t r e l Bonin P e t r e l Black-winged P e t r e l White-winged P e t r e l Collared P e t r e l Bulwer's P e t r e l Pale-footed Shearwater Sooty Shearwater Slender-bi l led Shearwater Wedge-tailed Shearwater ( l i g h t ) (dark) New Zealand Shearwater Christmas Shearwater Newell's Snearwater Sooty Storm P e t r e l Leach's Storm P e t r e l Wnite-throated Storm P e t r e l Red-tailed Tropicbird White-tailed Tropicbird Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd Mallard Jan Feb Mar Apr May Jun J u l Aug Sep Oct Nov Dec X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Table 21. (continued) Species Jan Feb Mar Apr May Jun J u l Aug Sep Oct Nov Dec Peregrine Falcon X American Golden Plover X X X Ruddy Turnstone X X X Red Phalarope X Skua X X X Pomarine Jaeger X X X X X X Long-tailed Jaeger X X X X X Laughing Gull X Gray-backed Tern X X X Sooty Tern X X X X X X X X X X X Brown Noddy X X X X X X White Tern X X X X X X X X X X X X Short-eared O w l X Table 22. Status* and a rea of d e r i v a t i o n of b i r d s observed a t sea near Johnston A t o l l Species Black-footed Albat ross Laysan Albat ross Dark-rumped P e t r e l Juan Fernandez P e t r e l White-necked P e t r e l T a h i t i P e t r e l Phoenix P e t r e l Mottled P e t r e l Herald P e t r e l Kermadec P e t r e l Bonin P e t r e l Black-winged P e t r e l White-winged P e t r e l Collared P e t r e l Bulwer's P e t r e l Pale-footed Shearwater Sooty Shearwater S ta tus Slender-bi l led Shearwater Wedge-tailed Shearwater ( l i g h t ) (dark) New Zealand Shearwater Christmas Shearwater Newell's Shearwater Sooty Storm P e t r e l ~ e a c h ' s Storm P e t r e l White-throated Storm P e t r e l Red-tailed Tropicbird Breeder Breeder Breeder Sojourner Migrant Sojourner Sojourner Trans ient Sojourner Sojourner Breeder Sojourner Soj ourner Sojourner Breeder Migrant Trans ient Trans ient Breeder Sojourner Migrant Breeder Breeder Breeder Sojourner Sojourner Breeder White-tailed Tropicbird Breeder Area of Origin Primary Secondary Northwestern Hawaiian I s l ands Northwestern Hawaiian I s l a n d s Main Hawaiian I s l ands Juan Fernandez I s l ands Kermadec I s l a n d s Various south P a c i f i c I s l ands Line and Phoenix I s l ands New Zealand Various south P a c i f i c I s l a n d s Various south P a c i f i c I s l ands Northwestern Hawaiian I s l ands Kermadec I s l a n d s Juan Fernandez I s l ands New Hebrides I s l a n d s Johnston A t o l l New Zealand New Zealand, A u s t r a l i a , Tasmania A u s t r a l i a , Tasmania Johnston A t o l l Line and Phoenix I s l ands New Zealand Johnston A t o l l Main Hawaiian I s l a n d s Northwestern Hawaiian I s l a n d s Aleut ians , Alaska Line and Phoenix I s l ands Johnston Main Hawaiian I s l a n d s Various south P a c i f i c i s l a n d s New Caledonia, F i j i Hawaiian, Line and Phoenix I s l a n d s southern South America Hawaiian I s l ands south P a c i f i c i s l a n d s Hawaiian I s l ands Kamachatka Various south P a c i f i c i s l a n d s Hawaiian I s l ands , Line and Phoenix I s l ands Line and Phoenix I s l ands Table 22. (continued) Blue-faced Booby Brown Booby Red-f ooted Booby Great F r iga teb i rd Mallard Peregr ine Falcon American Golden Plover Ruddy Turnstone Red Phalarope Skua Pomarine Jaeger Long-tailed Jaeger Laughing Gul l Gray-backed Tern Sooty Tern Brown Noddy Black Noddy White Tern Short-eared O w l S t a t u s Breeder Breeder Breeder Breeder Sojourner Sojourner Migrant Migrant Migrant Migrant Sojourner Migrant Sojourner Breeder Breeder Breeder Breeder Breeder Sojourner Area of Or ig in Primary Secondary Northwestern Hawaiian I s l ands Line and Phoenix I s l ands Johnston, Hawaiian I s l a n d s Line and Phoenix I s l ands Johnston, Hawaiian I s l a n d s Line and Phoenix I s l a n d s Johnston, Hawaiian I s l a n d s Line and Phoenix I s l ands North America North America and Asia S i b e r i a , Alaska S i b e r i a , Alaska S i b e r i a , Alaska New Zealand southern South America S i b e r i a , Alaska S ibe r i a , Alaska North America Johnston A t o l l Hawaiian I s l ands Johnston A t o l l Hawaiian I s l ands Johnston A t o l l Hawaiian I s l ands Johnston A t o l l Hawaiian I s l a n d s Johnston A t o l l Hawaiian I s l a n d s Main Hawaiian I s l ands North America "Breeder: breeds on nearby i s l a n d s ; Migrant: breeds elsewhere, but migrates t o nor th-cent ra l P a c i f i c ; Sojourner: breeds elsewhere, feeds i n nor th-cent ra l P a c i f i c Ocean on way t o d i s t a n t "wintering" ground; Transients: breeds elsewhere, moves through (but does not feed) nor th-cent ra l P a c i f i c Ocean on way t o d i s r an t "wintering" ground. - Means . . . . . Extremes Johnston Figure 41. Monthly diurnal seabird population fluctuations by species group within the at-sea area 175 miles southwest of Johnston Atoll, 1963-1967. 01 . J F M A M J J A S O N D Figure 42. Total nocturnal bird sightings at sea 175 miles southwest of Johnston Atoll, 1963-1967. E f f e c t s of Weather Pa t t e rns : The annual breeding and populat ion cyc le s presented i n t h e two preceding sec t ions were based on d a t a from normal weather p a t t e r n s from 1963 through 1968. The 1969 weather p a t t e r n , however, was abnormal. The 1969 season advanced normally u n t i l e a r l y February, when t h e weather p a t t e r n was d is rupted by a s e r i e s of low pressure d i s - turbances moving ac ross t h e a r e a from t h e west. During t h i s period winds s h i f t e d t o t h e south, occas ional ly southwest, and f o r one b r i e f period of s t rong winds and heavy r a i n , t o t h e north. Heavy r a i n s f e l l on s e v e r a l days during t h i s time, p a r t i c u l a r l y 3 and 8 February. The normal t r a d e wind p a t t e r n was re -es tab l i shed i n t h e l a s t ha l f of February, and no f u r t h e r weather d i s tu rbances occurred through t h e end of Apr i l . Concurrent wi th these weather changes came a dec l ine i n numbers and changes i n behavior of nea r ly a l l b i rd spec ies on t h e A t o l l . Most d r a s t i c a l l y influenced were t h e t h r e e major t e r n s : Sooty Terns, Gray- backed Terns, and Brown Noddies, but Christmas Shearwaters, Red-tailed Tropicbi rds , Brown Boobies, and Great F r iga teb i rds were not iceably a f f ec t ed . The connecting f a c t o r between t h e weather p a t t e r n and changes i n b i r d numbers remains obscure. Food a v a i l a b i l i t y may have decreased, making i t necessary f o r t h e b i r d s t o s t a y a t sea i n order t o f u l f i l l t h e i r n u t r i t i o n a l requirements, or perhaps t h e combination of changed wind p a t t e r n s and heavy cloud cover a f f e c t e d t h e naviga t ional pro- cedures of t h e b i r d s such t h a t they were unable t o f ind o r r e t u r n t o t h e i s l and . The r e s t o r a t i o n of normal weather i n l a t e February was followed by inc reases i n numbers and nes t ing a c t i v i t y i n a l l breeding b i r d s , but most were delayed i n comparison wi th o ther years . Sooty Terns were about t e n days behind t h e i r u s u a l c y c l e , and Brown Noddies d i d not commence laying u n t i l over a month l a t e r than i n former years . There was evidence t h a t unusual ly favorable feeding condi t ions prevai led i n March and e a r l y Apr i l . Sooty Terns spread t o occupy a g r e a t e r a r e a than ever before, and two-egg c lu t ches , many of them i d e n t i c a l i n propor t ions and color p a t t e r n , were more common than i n any o ther year . Brown Noddies acce le ra t ed lay ing s o t h a t , a l though t h e f i r s t eggs were not l a i d u n t i l 20 March, t h e t o t a l number l a i d by mid-April was t h r e e times t h e t o t a l produced by t h a t d a t e i n 1968. Gray-backed Terns re-nested beginning i n l a t e March, and l a i d s e v e r a l t i m e s more eggs than they normally l a y i n t h e re-nest ing at tempt. Four Brown Booby p a i r s l a i d three-egg c l u t c h e s , t h e f i r s t ever re - corded f o r Johnston A t o l l . The only outs tandingly c o n f l i c t i n g evidence comes from Christmas Shearwaters, which d id not begin lay ing I u n t i l e a r l y A p r i l , and produced only t h r e e eggs during Apr i l . Perhaps t h e shor tage of food i n February had a more d r a s t i c e f f e c t on t h e s e b i r d s because of t h e l a r g e r s i z e of t h e i r egg and consequent g r e a t e r need f o r heavy feeding during i t s development. Shearwaters a r e thought t o l a y no replacement eggs, and t h e forced r e so rp t ion of a p a r t i a l l y developed egg might block f u r t h e r egg production i n t h a t year . Ecological D i s t r i b u t i o n Within t h e A t o l l The four i s l a n d s a t Johnston A t o l l d i f f e r i n s i z e , he igh t , s o i l , vege ta t ion , fresh-water supply, and degree of human d is turbance . Major d i f f e r e n c e s i n av i f auna l d i s t r i b u t i o n , e s p e c i a l l y breeders , a r e found between d i s tu rbed and non-distrubed i s l a n d s (Table 18) . Of t h e 56 b i r d spec ie s known from t h e a t o l l , 52 a r e known from Sand Is land . Furthermore, 44 spec ie s a r e known from t h e o r i g i n a l po r t ion , while 35 a r e from t h e man-made p a r t . I n a l l , 35 spec ie s a r e known from Johnston I s l and , while e i g h t a r e from Akau I s l and and f i v e a r e recorded from Hikina Is land . Seabirds: Breeding: Th i r t een breeding seabi rd s p e c i e s a r e known from Sand I s l and ; 11 spec ie s p re sen t ly n e s t t h e r e (Table 18 ) . Likewise 14 breeding spec ie s a r e known from Johnston I s l and ; however, only t h r e e spec ie s c u r r e n t l y n e s t t he re . One s p e c i e s has been known t o n e s t i n r ecen t yea r s on man-made Akau I s l and ; two have nested on man-made Hikina Is land . V i s i t o r s : A l l seven seabi rd v i s i t o r s a r e known from Sand I s l and , poss ib ly a t t r a c t e d t h e r e by o ther s eab i rd spec ies ; six a r e recorded from t h e o r i g i n a l po r t ion , while only two a r e from t h e man- made p a r t (Table 18 ) . Three spec ie s a r e known from Johnston Is land . One spec ie s i s known from Akau I s l and , none from Hikina Is land . Waterfowl, Marsh, and Land Birds: Regular Migrants: A l l seven r egu la r migrants a r e known from both o r i g i n a l and man-made por t ions of Sand I s l and (Table 18) . Likewise, a l l bu t one species--the P e c t o r a l Sandpiper--are known from Johnston I s l and . Four spec ie s have been recorded from Akau I s l and ; t h r e e spec ie s a r e from Hikina I s l and . I r r e g u l a r V i s i t o r s , S t r agg le r s , and Accidentals : I n a l l , 22 i r r e g u l a r v i s i t o r , s t r a g g l e r and a c c i d e n t a l waterfowl, marsh and land b i r d spec ie s a r e known from Sand I s l and : 16 from t h e o r i g i n a l po r t ion and 12 from t h e man-made p a r t . Ten spec ie s have been recorded from Johnston I s l and . Only one s p e c i e s is known from Akau Is land; one i s known from Hikina Is land . In t roduct ions : Two of t h e introduced spec ie s a r e known from Johnston I s l and . One spec ie s has been recorded from Sand Is land . I s land Accounts: Avifaunal components of each i s l a n d , l i s t e d a lphabe t i ca l ly , a r e discussed i n t h e fol lowing sec t ion . Akau Is land: Eight b i r d spec ie s have been recorded (Table 18) The i s l and was b u i l t i n 1964 and t h e low populat ion and breeding numbers recorded s i n c e a r e due p r imar i ly t o human d is turbance . Tota l daytime populat ions a r e extremely small ; populat ions, e s p e c i a l l y of roos t ing shorebi rds , probably inc rease a t n igh t . Only one species--Gray-backed Tern--has nested on Akau. That occurred only i n 1964 a f t e r t h e i s l and was completed, but before bui ld ing cons t ruc t ion s t a r t e d . The n e s t s were placed on bare sand but most were destroyed by cons t ruc t ion ; none has nested s ince . Great F r iga teb i rds roos ted on va r ious ob jec t s on t h e i s l a n d , and Brown Boobies probably r o o s t here occas ional ly . White-tailed Tropicbi rds have a l s o been seen f l y i n g over t h e i s l and . Four r egu la r migrant shorebirds--American Golden Plover , Ruddy Turnstone, Br is t le - th ighed Curlew, and Wandering Tattler--have been observed on t h e beaches of Akau. Only one i r r e g u l a r v i s i to r - - a land bird--has been recorded. Short-eared O w l s sometimes roosted he re when present on t h e a t o l l . Because of human i n h a b i t a t i o n (bui ld ings , e t c . ) , small s i z e , and l a c k of nes t ing h a b i t a t , Akau I s l and a t t r a c t e d very few b i r d spec ie s . However, wi th t h e proposed reduced human a c t i v i t y a f t e r f a l l 1973, t h e i s l a n d w i l l no doubt a t t r a c t a d d i t i o n a l b i r d spec ies and perhaps even breeding seabi rd spec ie s . Hikina Is land: Since Hikina Is land was b u i l t i n 1964 only s i x spec ie s of b i r d s have been recorded, pr imar i ly because of human d is turbance (Table 18) . From 1964 through 1969 one seab i rd occas ional ly roosted he re and t h r e e of t h e r egu la r migrant shorebi rds commonly feed on t h e beaches. Roosting shorebi rds frequented t h e i s l and a t n i g h t . Hikina I s l and has continued t o a t t r a c t small numbers of b i rd spec ie s because of human d i s tu rbance , t h e i s l a n d ' s small s i z e , and a l a c k of s u i t a b l e nes t ing h a b i t a t . Two spec ie s of s eab i rds , however d i d n e s t i n 1973 because of reduced human d is turbance . These two spec ie s and most l i k e l y o the r s w i l l cont inue t o breed h e r e a s long a s human d is turbance i s kept a t a minimum. Johnston Is land: Birds t o t a l i n g 35 spec ie s have been recorded from Johnston Is land a able' 18) . Of these 35 spec ie s , 17 were sea- b i r d s and 18 were waterfowl, marsh, and land b i r d s . Of t h e 1 7 spec ie s of s eab i rds , four p re sen t ly breed and ten formerly bred on t h e i s l a n d . Since 1963, only one of t hese t en former breeders has ever been recorded from Johnston I s l a n d . This d e c l i n e i n breeding spec ie s , a s wel l a s a correspondingly low b i r d popula t ion , can be d i r e c t l y a t t r i b u t e d t o human d is turbance beginning i n t h e l a t e 1930's. P resen t ly White Terns u t i l i z e t h e t a l l e s t Casuarina t r e e s and v a r i o u s man-made o b j e c t s on which t o r o o s t and l a y t h e i r eggs. Like- wise, Black Noddies r o o s t and n e s t i n t h e t a l l e s t Casuarina t r e e s . Red-tailed Tropicbi rds n e s t under t h e l a r g e r bushes--part icular ly PZuchea--scattered about t h e i s l and . Wedge-tailed Shearwaters n e s t under t h e denser bushes and have been known t o n e s t under va r ious bui ld ings . Sand Is land: Fifty-two spec ie s of b i r d s have been recorded from Sand I s l and (Table 1 8 ) . Of t h e s e 52 spec ie s , 44 a r e lcnown from t h e o r i g i n a l po r t ion and 35 a r e known from the man-made por t ion . Of t h e 35 spec ie s known from t h e man-made por t ion , t h r e e spec ie s of s eab i rds p resen t ly breed. An a d d i t i o n a l s i x spec ie s of s eab i rds nested he re while t h e i s l a n d was uninhabited during t h e l a t e 1940's and 1950's . Bulwer's P e t r e l s p re sen t ly n e s t i n c a v i t i e s formed by t h e rocks along t h e causeway. Red-tailed Tropicbi rds and a t t imes Wedge-tailed Shearwaters n e s t under t h e dense bushes, e s p e c i a l l y ScaevoZa and l 'ournefortia, growing around t h e bui ld ings . Of t h e 44 spec ie s recorded from t h e o r i g i n a l po r t ion , I1 spec ie s of s eab i rds p resen t ly breed. I n a d d i t i o n , two breeding s p e c i e s of s eab i rds no longer n e s t e i t h e r h e r e or elsewhere on t h e a t o l l . The populat ion cyc les shown i n F igure 38 a r e predominantly of b i r d s on Sand Is land . During t h e sp r ing and summer, Sooty Terns n e s t on t h e bare ground over most of t h e i s l and (Fig. 35) and a r e t h e most prominent spec ies . The 1963 nes t ing a r e a s f o r o the r spec ie s a r e shown i n Figures 43 and 44. Nesting a r e a s a r e a l s o i l l u s t r a t e d under ind iv idua l spec ie s accounts . Brown Noddies n e s t on t h e ground around t h e periphery of t h e i s l a n d . Black Noddies n e s t i n t h e low Amaranthus bushes, when present . Gray-backed Terns n e s t on t h e ground on t h e no r theas t peninsula and t h e southwest i s l e t . Red- t a i l e d Tropicbi rds n e s t under low vege ta t ion , and va r ious cement s l a b s and o ther o b j e c t s , about t h e i s l and . Wedge-tailed Shearwaters n e s t i n burrows over much of the i s l a n d ; most burrows a r e placed so t h a t vege ta t ion r o o t s he lp support t h e surrounding s o i l . Christmas Shearwaters, and a t t imes Bulwer's P e t r e l s , n e s t under cement s l a b s and va r ious wooden timbers ly ing about on the su r face of t h e i s l and . Brown Boobies n e s t on t h e ground on t h e southeas t h i l l , t h e south edge, t h e no r theas t peninsula , and t h e southwest i s l e t . Red-footed Boobies bui ld t h e i r n e s t s on t h e e a s t h i l l , on t h e Toumefor t ia bush n o r t h e a s t of t h e t r ansmi t t e r bu i ld ings , and on t h e va r ious p i l i n g s around t h e i s l a n d . Great F r i g a t e b i r d s n e s t along t h e e a s t h i l l and t h e south edge. 0 Wedge-tailed Shearwater Brawn Noddy O Gray-backed Tern N * Christmas Shearwater 0 Brown Booby Figure 43. Nesting a r e a s or ground n e s t i n g b i r d s (except Sooty Terns) on t h e o r i g i n a l po r t ion of Sand I s l and , Johnston A t o l l , 1963. 0 100 200 pLL.E;3 Feet Figure 44. Nesting a r e a s of b i r d s which nonnally nes r i n low v e g e t a t i o n on t h e o r i g i n a l po r t ion of Sand I s l and , Johnston A t o l l , 1963, Mor ta l i t y The l a r g e s t cause of m o r t a l i t y during t h e POBSP s t u d i e s was t h e guywire system of t h e LORAN-C antenna on Sand I s l and . This system contained 24 top-loaded guywires which s t r e t ched from t h e top of t h e 625-foot tower t o concre te anchors loca ted i n t h e lagoon i n a c i r c l e around t h e i s land . I n a d d i t i o n , t h r e e o ther s e t s of guywires s t r e t c h e d from p a r t way up t h e tower t o two s e t s of concre te anchors loca ted on o r near t h e i s l and i t s e l f . 0ne.of t hese l a t t e r s e t s , s t r e t ched low a c r o s s t h e southeas t corner of t h e i s l a n d , accounted f o r a n abnormally high amount of m o r t a l i t y because i t crossed a heavily-used b i r d a rea and was c l o s e r t o t h e ground than t h e o the r guywires. Table 23 shows monthly m o r t a l i t y of Sooty Terns from t h i s guywire system recorded during f i v e months of t h e breeding season i n 1965. Since roughly 600,000 a d u l t Sooty Terns use t h e i s l and during t h e breeding season and about 60,000 young f l e d g e annual ly, t h e 5,062 dead b i r d s represent about 0.8 percent of t h e t o t a l populat ion. Adult m o r t a l i t y is about 0.5 percent , while immature m o r t a l i t y i s about 3.7 percent . Adult Sooty Tern l o s s e s were g r e a t e s t j u s t a s egg l ay ing began (March) when h ighes t numbers swir led low over t h e i s l and ; ch ick l o s s e s were h ighes t when they began t o f l y . Of t h e 5,062 dead b i r d s 14.4 percent were banded ( a d u l t s 9.2 percent , immatures 21.1 percent ) . There appeared t o be a d e c l i n e i n numbers of a d u l t Sooty Terns l o s t t o t h e guywires during t h e l a s t two years (1968 and 1969) of POBSP s t u d i e s . Poss ib ly the remaining b i r d s were becoming wary of t h e wires a s undoubtedly most a d u l t s had had c l o s e brushes wi th t h e wires and i t is poss ib l e they could l e a r n t o avoid them. Mor ta l i t y r eco rds were a l s o kept f o r o t h e r spec ie s during t h e five-month s tudy. Although not a s spec tacu la r number-wise a s f o r Sooty Terns, two o the r spec ies a c t u a l l y had higher m o r t a l i t y r a t e s . Su rp r i s ing ly , shorebi rds had t h e h ighes t r a t e a t 5 .8 percent (n ine dead). Great F r i g a t e b i r d s were next a t 1.8 percent (24 dead, 8 . 3 percent banded). Although no f i g u r e s a r e a v a i l a b l e , a high percentage of t h e Great F r i g a t e b i r d s t h a t fledged each year broke t h e i r wings on t h e s e wires and d ied . The m o r t a l i t y r a t e s f o r Brown Noddies (33 dead, 18.2 percent banded) and Wedge-tailed Shearwaters (25 dead, 44 percent banded) were t h e same--0.8 percent--as f o r Sooty Terns. Red-footed Boobies (n ine dead, 11.1 percent banded) had 0.3 percent m o r t a l i t y , whereas Red-tailed Tropicbi rds (one dead) had 0.5 percent m o r t a l i t y . Dead b i r d s from t h e guywires presented l i t t l e d i sposa l problem because of t h e presence of dermestid b e e t l e s (Dermestes a t e r ) . These i n s e c t s were a t t h e i r lowest numbers i n mid-winter when re- turn ing Sooty Terns f i r s t began h i t t i n g t h e wi re s . The population quickly responded t o t h e inc rease i n food and by t h e time t h e t e r n s reached t h e i r peak abundance, t h e dermest ids could e l imina te T a b l e 23. Soo ty T e r n m o r t a l i t y f rom guywi re s t r i k e s , Sand I s l a n d , March - J u l y 1965 A d u l t s Immatures Combined T o t a l No. P e r c e n t T o t a l No. P e r c e n t T o t a l No. P e r c e n t Month K i l l e d Banded Banded K i l l e d Banded Banded K i l l e d Banded Banded March 1 , 3 2 0 122 9.2 1 , 3 2 0 122 9.2 A p r i l 438 4 0 9 .1 438 4 0 9 . 1 May 312 29 9.3 153 27 1 7 . 6 4 65 5 6 12 .0 J u n e 527 3 6 6 .8 1 ,792 335 18.7 2 ,319 3 7 1 16 .0 .July 2 5 1 3 5 1 3 . 9 269 1 0 5 39.0 520 14 0 26.9 ca rcasses , even of f r i g a t e b i r d s and boobies, i n l i t t l e more than a day. This made i t unnecessary, and even undes i rab le , t o i n i t i a t e any kind of dead b i rd removal program except where ca rcas ses ap- peared near bui ld ings . Of l e s s e r importance i n c leaning carcasses were cockroaches, a n t s , and f l i e s . Fly popula t ions gene ra l ly were low because dermest ids devoured ca rcas ses too quickly t o a l low f l y l a rvae to develop--indeed any f l y l a r v a e on a c a r c a s s usua l ly were devoured by t h e a n t s and dermest ids . Banding and I n t e r i s l a n d Movement The u s e of U .S . F i sh and Wi ld l i f e Serv ice bands i s a widely accepted method f o r marking b i r d s . By using these s e r i a l l y numbered, metal (usua l ly aluminum), l e g bands a t Johnston A t o l l , and throughout t h e c e n t r a l P a c i f i c , t h e POBSP was a b l e t o (1) s tudy b i r d migra t ion , (2) ob ta in spec ies longevi ty , (3) recognize ind iv idua l s from t h e i r neighbors , and (4) e s t ima te populat ions by t h e mark-and-recapture method. To f a c i l i t a t e s i g h t i n g Johnston-banded b i r d s a t sea and on d i s t a n t i s l a n d s , most banded a d u l t s and young were a l s o tagged with a blaze-orange, p l a s t i c , l e g s treamer. Banding: N.P. Ashmole, then of the B.P. Bishop Museum, Honolulu, Hawaii, banded t h e f i r s t b i r d s a t Johnston A t o l l i n February 1963; he banded 72 seab i rds of f i v e spec ie s . B i rds t o t a l i n g 303,732 of 21 spec ie s were banded a t Johnston A t o l l by POBSP personnel from J u l y 1963 through September 1969 (Table 24). The POBSP banded more b i r d s h e r e than anywhere e l s e i n t h e c e n t r a l P a c i f i c . Amerson, then of t h e Smithsonian I n s t i t u t i o n , banded 97 b i r d s of f i v e spec ie s i n November 1973. From 1967 through 1969, primary emphasis turned t o r ecap tu re of banded b i r d s , but chicks of most spec ie s were banded i n a s l a r g e numbers a s poss ib l e i n order t o continue t o mark known-age b i r d s f o r f u t u r e s t u d i e s . By f a r t h e major i ty of t hese 303,901 b i r d s was banded a t Sand I s l and . Only a few of two species--Red-tailed Tropicbird and White Tern--were banded a t Johnston I s l and . None was banded a t Akau and Hikina I s l ands . Of t h e t o t a l banded (Table 24) the re were: 285,526 Sooty Terns, 7,979 Brown Noddies, and 6,517 Wedge-tailed Shearwaters, 1,047 Red- footed Boobies, and 1,005 Great F r iga teb i rds ; t h e remaining 16 s p e c i e s only accounted f o r 1,827 banded b i r d s . I n t e r i s l a n d Movement: I n a l l , 18 spec ie s t o t a l i n g 60,932 b i r d s have been recaptured a t Johnston A t o l l s i n c e 1958 (Table 25). Of t h i s t o t a l , 60,526 b i r d s were o r i g i n a l l y banded on t h e a t o l l , while 406 were banded elsewhere. Table 24. Birds banded a t Johnston A t o l l , 1963 t o 1973 1963 1964 1965 1966 1967 1968 1969 1973 To ta l Laysan Albat ross Bulwer's P e t r e l Wedge-tailed Shearwater Christmas Shearwater Red-billed Tropicbird Red-tailed Tropicbird White-tailed Tropicbird Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd P i n t a i l American Golden Plover Wandering T a t t l e r Ruddy Turnstone Gray-backed Tern Sooty Tern Blue-gray Noddy Brown Xoddy Black Noddy White Tern T o t a l s *Totals include 2 Brown Boobies, 3 Christmas Shearwaters, 5 Great F r i g a t e b i r d s , 17 Brown Noddies, and 45 Sooty Terns, a l l banded by N.P. Ashmole i n February 1963. T a b l e 25. Year ly band r e t u r n t o t a l s f o r Johns ton A t o l l 1958 1963 1964 1965 1966 1967 1968 Other J A Other J A Other JA Other JA Other J A Other J A Other Bulwer ' s P e t r e l 15 1 9 25 2 9 Wedge-tailed Shearwater 2 263 697 1 , 0 5 1 2 200 383 Chr i s tmas Shearwater 14 2 2 13 17 14 Red- ta i l ed T r o p i c b i r d 8 64 87 111 1 0 1 1 Blue-faced Booby 1 4 4 9 3 1 1 4 Brown Booby 1 3 l** 7 1 76 1 0 5 112 Red-footed Booby 2 14 24 30 70 24 39 1 6 7 G r e a t F r i g a t e b i r d 11 63 2 146 4 39 3 34 1 0 P i n t a i l 1 American Golden P lover 2 (2 ) 1 1 1 Wandering T a t t l e r Ruddy Turns tone 2 1 Gray-backed Tern 2 6 2 2 Sooty Tern 799 1 3 ,173 6 10,799 16" 10,017 3 1 13,902 3 1 E l e g a n t Tern Brown Noddy 4 2 5 1 3 103 194 1 96 278 1 Black Noddy 2 4 1 1 1 2 5 White Tern f T o t a l s T a b l e 25. ( c o n t i n u e d ) 1969 197 0 1 9 7 1 1972 1973 T o t a l JA Othe r JA Othe r JA Othe r JA Othe r JA Othe r JA Othe r Bu lwer ' s P e t r e l 40 128 0 Wedge-tai led Shea rwa te r 72 2 4 9 2 ,683 2 C h r i s t m a s Shea rwa te r 1 9 9 9 0 R e d - t a i l e d T r o p i c b i r d 129 3 2 2 504 4 Blue-faced Booby 2 6 23 Brown Booby 123 1 1 1+ 1 1 5 03 3 Red-footed Booby 3 0 53 1 116 194 G r e a t F r i g a t e b i r d 47 9 1 2 348 29 P i n t a i l 0 1 American Golden P l o v e r 3 (1) 8 0 Wandering. T a t t l e r (1) 0 0 Ruddy T u r n s t o n e 0 3 Gray-backed Tern 11 23 0 Soo ty Tern 6 ,846 1 0 9,554 37 1 5 1 2 1 55,206 132 E l e g a n t Te rn 1 0 1 Brown Noddy 145 4 7 882 7 B lack Noddy 8 2 20 6 White Te rn 0 1 T o t a l s 7 ,473 8 1 5 0 9 ,565 40 1 5 0 1 4 0 0 60 ,526 406 *Does n o t i n c l u d e o n e Phoen ix b i r d n o t a c c e p t e d . **One band found , a c t u a l d a t e n o t known; n o t i n c l u d e d i n t o t a l s . ( )Numbers i n p a r e n t h e s i s a r e s i g h t i n g s of s t r e a m e r e d b i r d s and a r e n o t i n c l u d e d i n t o t a l s . The 406 captures of b i r d s from other l o c a l i t i e s involve 13 spec ie s , but r ep resen t only 388 b i rds a s some were captured more than once. These b i r d s were o r i g i n a l l y banded a t 15 l o c a l i t i e s (Table 26). The ma jo r i ty came from t h e northwestern Hawaiian I s l a n d s with the most from French F r i g a t e Shoals (127 b i r d s , or 33 percent ) . Laysan I s l and was second a t 51 b i r d s (13 percent ) and Kure A t o l l t h i r d a t 40 b i rds (10 percent ) . Wake A t o l l , however, was second o v e r a l l wi th 60 b i rds (15 percent ) moving t o Johnston. Only f i v e b i r d s , t h r e e being ques t ionable r eco rds , poss ib ly moved to Johnston A t o l l from i s l a n d s t o t h e south. I n add i t ion t o b i r d s coming t o t h e A t o l l , 345 b i r d s of 12 spec ies o r i g i n a l l y banded a t Johnston A t o l l were captured on 20 o ther a t o l l s o r i s l a n d groups and from 13 a t -sea l o c a l i t i e s (Table 26). Of these 345 banded b i r d s , 273 (79 percent) went t o t h e Hawaiian I s l a n d s and Wake, while 50 (17 percent) moved to t h e west and southwest P a c i f i c . Twelve banded b i r d s (most ques t ionable records) poss ib ly moved t o t h e Phoenix I s l ands . The number of i nd iv idua l banded b i r d s involved i n i n t e r i s l a n d movement, both t o and from t h e a t o l l , t o t a l s 733. French F r i g a t e Shoals (232 b i r d s ) , Laysan I s l and (92 b i r d s ) , Kure A t o l l (75 b i r d s ) and Wake A t o l l (73 b i r d s ) , i n t h a t o rde r , a r e the ? . to l l s most f r equen t ly involved. The o v e r a l l POBSP banding and r ecap tu re program i n t h e c e n t r a l P a c i f i c has shown t h a t b i r d movement between t h e Line and Phoenix I s l a n d s a rea and t h e Hawaiian I s l ands and Johnston a rea was v i r t u a l l y n i l (Amerson, 1968). Movements between i s l a n d s wi th in each of these a r e a s was much l a r g e r , and t h e number of b i r d s r e tu rn ing t o t h e i r i s l and of banding was s t i l l g r e a t e r . Banded b i r d s from both a r e a s , however, were recaptured i n t h e f a r western P a c i f i c . Banding da ta seem t o i n d i c a t e t h a t Johnston A t o l l i s a major f o c a l poin t f o r i n t e r i s l a n d movements i n the nor th-cent ra l P a c i f i c . Movements t o and from Johnston A t o l l a r e h ighes t among a l l t h e i s l a n d s i n t h i s a r e a . This may simply r e s u l t from fu l l - t ime POBSP personnel coverage a t Johnston, or i t may a c t u a l l y r e f l e c t a high degree of movement to and from t h e a t o l l (POBSP, 1967b). AviEaunal A f f i n i t i e s The Johnston A t o l l av i fauna shows c l e a r a f f i n i t i e s with t h e Hawaiian I s l ands , both taxonomically and i n movement p a t t e r n s . These a r e , of course, the c l o s e s t i s l a n d s to Johnston. P a r t i c u l a r l y s i g n i f i c a n t a r e movements of breeding spec ies : Red-footed Boobies, Great F r i g a t e b i r d s , Blue-faced Boobies, Brown Noddies, Wedge-tailed Shearwaters, and Black Noddies ( l i s t i s i n descend- ing order of numbers of i n t e r i s l a n d movements from Table 26) , i n which most of t h e recorded movements involving Johnston a r e with t h e Hawaiian I s l ands . The major exceptions a r e Sooty Terns and Red-tailed Tropicbi rds , Table 26. I n t e r i s l a n d movement of banded b i r d s involving Johnston A t o l l Wedge-tailed Shearwater 2 6 Red-tailed Tropicbird Blue-faced Booby 12 1 Brown Booby Red-footed Booby 19 16 61 Great riga ate bird 1 23 P i n t a i l Ruddy Turnstone Sootv Tern Elegant Tern Brown Noddy Black Noddy White Tern 1 Tota l (To) 19 21 127 1 5 1 1 3 1 7 29 40 60 2 From Johnston to : Laysan Albat ross Wedge-tailed Shearwater Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd Ruddy Turnstone Gray-backed Tern Sooty Tern Brown Noddy Black Noddy White Tern To ta l (From) Grand Total Table 26. (continued) Wedge-tailed Shearwater Red-tailed Tropicbird Blue-faced Booby Brown Booby Red-footed Booby Great F r iga teb i rd P i n t a i l Ruddy Turnstone Sooty Tern Elegant Tern Brown ~ o d d y Black Noddy White Tern 1 Tota l (To) 4 1 1 2 388 From Johnston t o : Laysan Albat ross Wedge-tailed Shearwater Blue-faced Booby Brown Booby 1 Red-footed Booby Great F r iga teb i rd 1 Ruddy Turnstone Gray-backed Tern 1 Sooty Tern 2 2 13 5 2 1 0* Brown Noddy 2 2 1 4 1 2** Black Noddy White Tern 1 z Tota l (From) 4 2 16 5 2 4 2 2 12 13 1 345 -4 Grand T o t a l 4 2 16 5 2 4 2 2 16 1 13 2 2 733 *Questionable; **One taken o f f shore ; ( )S ight ing only. i n which a d i sp ropor t iona te ly high number of movements a r e from Wake I s l and , which l i e s west of Johnston a t a g r e a t e r d i s t ance than any of t h e Hawaiian I s l ands . Furthermore, those breeding spec ie s f o r which subspecies or co lor phases can be used t o determine a f f i n i t i e s , a r e a l l i e d with t h e northern i s l ands : Wedge-tailed Shearwater, Red-footed Booby and Blue- gray Noddy a r e of the t y p i c a l nor thern co lo r phases (or subspecies i n t h e case of t h e Blue-gray Noddy). A s f o r t h e non-breeding spec ie s , movements of b i r d s not banded but c o l l e c t e d , however, rernain mostly from t h e Hawaiian Is lands : Newell's Shearwater, Sooty Storm P e t r e l , White-tailed Tropicbi rd , C a t t l e Egre t , Blue-gray Noddy, Short-eared O w l , and Japanese White-eye. There a r e a few recorded movements from t h e south and e a s t . The Phoenix P e t r e l and Lesser F r i g a t e b i r d s a r e e q u a t o r i a l breeders , although Lesser F r i g a t e s have been recorded from Wake and t h e northwestern Hawaiians, and may have a c i r c u l a r migrat ion p a t t e r n t h a t inc ludes (occasional ly) Johnston on t h e r e t u r n t o t h e e q u a t o r i a l breeding i s l ands . From t h e eas t e rn P a c i f i c comes t h e Red-billed Tropicbird, and from the no r theas t , poss ib ly v i a Hawaii, have come a number of acc iden ta l s : Glaucous-winged Gull , Laughing Gul l , Frankl in ' s Gul l , Elegant Tern, and possibly Herring and Western Gulls . Techniques Although most of t h e study techniques used by t h e POBSP a t Johnston A t o l l were s traight-forward and se1.f-expl.anatory, a few comments on tile accuracy and r e l a t i v e va.lues of t h e r e s u l t s a r e necessary t o c l a r i f y t h e meaning of t h e d a t a , and t o e~nphasize t h a t i n sonre cases , t a b l e s and d iscuss ion a r e carefu:lly labell-ed t o s t a t e what t h e f i g u r e s actua.lly r ep resen t , r a t h e r than what they i d e a 1 . l ~ should represent . For exaliiple, reported numbers of b i r d s ill tile scniimoni-hly r e p o r t s i d e a l l y were t o be the t o t a l number of b i r d s iisi.ng t'he atol.1. during t h e period i n quest ion. C$.ear:Ly, t h i s f i g u r e i s una t t a inab le f o r even the most conspicuous aiicl casi1.y enumerated spec ies . It would r e q u i r e cons tant su rve i l l ance on t h e e n t i r e a t o l l f o r t h e e n t i r e period, with a.11 new b i r d s d e t e c t a b l e . Thus t h e f i g u r e can mean no more than the numher of i.ndivi.duals o:E a given spec ie s known to use the ato1.l during the per iod . I n many cases f i g u r e s reported r e a l l y a r e not es t imates of t o t a l nuntbers usj.ng t h e i s l a n d s , but of maximum seen a t one time, which i s probably f a r lower i n nea r ly every in s t ance than t h e t o t a l number us ing t h e i s l a n d during t h e per iod , because i t i s extremely un l ike ly t h a t a l l would be present a t any one time, even a t light f o r roos t ing . Reported counts , then , should be regarded a s ind ices t o t h e numbers using t h e a t o l l , r a t h e r than accura t e e s t ima tes , although i n a few cases they may be f a i r l y accura te . I n gene ra l , t h e fewer ind iv idua l s and t o a l e s s e r ex ten t , the l a r g e r and more conspicuous t h e b i r d , t h e more l i k e l y i s t h e count t o accura t e ly represent t h e t r u e number of i nd iv idua l s using t h e i s l and . An extreme example i s t h e C a t t l e Egre t , which occurred no more than two a t once, were comparatively l a r g e and conspicuous and were highly p red ic t ab le i n h a b i t s and h a b i t a t . It is recognized t h a t t h e capture-mark-recapture (or observe) c a l c u l a t i o n s f o r populat ions do not meet t h e assumption of no turnover i n t h e populat ion between marking and observat ion. However, i t i s t h e only technique a v a i l a b l e i n most cases and t h e e s t ima tes a r e presented i n a few cases where no other ob jec t ive e s t ima tes a r e a v a i l a b l e . They may even be used f o r es t imat ing t h e r a t e of turnover , a s f o r example i n Sooty Terns, Black Noddies, and White Terns. Some ind ica t ion of populat ions a r e thus poss ib l e . Rapid turnover of personnel necessa r i ly had a d e l e t e r i o u s e f f e c t on d a t a ga ther ing , through s t u d i e s being dropped o r changed when per- sonnel changed. However, a l a r g e body of r e l i a b l e information was assembled i n t h e f i e l d notes and semimonthly r e p o r t s . Bas ica l ly these spec ie s accounts w i l l summarize i n d e t a i l t hose a spec t s of t h e l i f e h i s t o r i e s and populat ions f o r which comparable d a t a were obtained f o r a l l spec ie s of eco log ica l equivalence. Specimens The f i r s t s c i e n t i f i c b i rd specimens were co l l ec t ed by Kern i n March 1859 when t h e U.S. Schooner FENIMORE COOPER v i s i t e d Johnston A t o l l (Brooke, ms.). What spec ie s were c o l l e c t e d a r e not known; however, they were l o s t when t h e sh ip l a t e r burned and sank i n Japan (Brooke, 1955). P r i o r t o t h e f i r s t POBSP i n Ju ly 1963, 93 specimens of 1.6 b i rd s j cc i e s - - a l l co l l ec t ed by Alexander Wetmore i n J u l y 1923--were known L: om Johnston At0: i . l . POBSP personnel co l l ec t ed 616 specimens of 41 t p c c i e s from 1963 through 1969. These 709 specimens of 4 1 spec:ics :ire a:l.L iiousecl i n t h e b i rd co1.lection of t h e Natj~onal Muscum of Natural Eiistory (USNN) , Washington, D .C. Fifty-one new spec ie s distribut:i .onal records--two f i r s t specimen records of spec ie s previous ly unlcno~n? f o r t h e c e n t r a l Pac.i:fic Ocean, one f i r s t specimen record of a spec ies previous ly known on:Ly from a s i g h t record i n t h e nor th-cent ra l P a c i f i c Ocean, 38 f i r s t specimen records f o r t h e a t o l l , and t e n f i r s t s i g h t records--and four new spec ie s breed5.ng records a r e repor ted he re in . Table 27 sunimarizes t h e s e gpecimen and d i s t r i b u t i o n a l records . These records f a l l i n t o two ca t egor i e s , one composed of spec ie s t h a t regular3.y occur on i s l a n d s i n t h e nor th-cent ra l P a c i f i c Ocean but which cannot be con- s idered unusual , and t h e o ther group composed of spec ie s of uncommon o r seldom-documented occurrence on i s l a n d s i n t h e nor th-cent ra l P a c i f i c Ocean. T a b l e 27. B i r d specimens and summary of new r e c o r d s from J o h n s t o n A t o l l C o l l e c t e d Specimens S p e c i e s Wetmore POBSP T o t a l New Records Phoenix P e t r e l Bulwer' s P e t r e l Wedge-tai led Shearwater Chr i s tmas Shearwater Newel l ' s Shearwater Sooty Storm P e t r e l Red- ta i l ed T r o p i c b i r d Blue-faced Booby Brown Booby Red-footed Booby Grea t F r i g a t e b i r d L e s s e r F r i g a t e b i r d C a t t l e E g r e t P i n t a i l American Wigeon Nor the rn Shove le r Domestic Chicken P e r e g r i n e Falcon American Golden P lover B l a c k - b e l l i e d P lover Semipalmated P lover B r i s t l e - t h i g h e d Curlew L e s s e r Y e l l o . ~ l e g s S p o t t e d Sandpiper Willet Wandering T a t t l e r Ruddy Turns tone Dowitcher s p e c i e s Sander l i n g Western Sandpiper P e c t o r a l Sandpiper S h a r p - t a i l e d Sandpiper Buf ? -b reas ted Sandpiper Ruff Wi l son ' s P h a l a r o p e Glaucous-winged G u l l H e r r i n g G u l l Laughing G u l l F r a n k l i n ' s G u l l G u l l s p e c i e s Gray-backed Tern Sooty Tern E l e g a n t T e r n ' Blue-gray Noddy Brawn Noddy Blaclc Noddy 1 sr 1 0 sr, b r 100 sr 11 sr , b r 2 ST 1 sr 2 9 sr 1 0 sr , br* 14 sr 2 9 sr 67 sr 1 9 sr 1 sr 2 sr 5 sr 1 sr 1 sr , SFR r 4 ST 1 0 sr r 1 sr 2 sr 1 ST 1 sr 1 sr, SR 2 sr r 1 1 sr 1** r 1 9 ST 236 ST 1 sr , SFR 3 sr 84 sr 6 sr Table 27. (cont . ) Species Collected Specimens Wetmore POBSP To ta l New Records White Tern 7 7 14 ST Rock Dove r , br Skylark r Japanese White-eye 2 2 Socie ty Finch r T o t a l s 93 616 709 b r = f i r s t breeding record; r = f i r s t s i g h t record; s r = f i r s t specimen record; SR=f i r s t specimen confirmation of a spec ies previously known only from a s i g h t record i n t h e nor th-cent ra l P a c i f i c Ocean; SFR=first specimen record f o r a spec ie s previous ly unknown from t h e c e n t r a l P a c i f i c Ocean. "ext i rpa ted; **specimen l o s t . Species Accounts For d e s c r i p t i o n s and i l l u s t r a t i o n of t h e 56 spec ie s of b i r d s recorded he re in , the reader i s r e f e r r e d to t h e o rn i tho log ica l sources c i t e d previous ly , e s p e c i a l l y King (1967). BLACK-FOOTED ALBATROSS Diomadea nigripes s t a t u s Former uncommon breeding spec ie s ; r e c e n t regular but s ca rce winter v i s i t o r a t sea near Johnston Ato l l ; two quest ionable records of b i r d s landing on Johnston and Sand I s l a n d s during t h e 1960's . Small numbers probably nested on t h e sandy por t ions of Sand I s l a n d , a s w e l l a s on Johnston I s l and , p r i o r t o m i l i t a r y occupancy. Ecologica l D i s t r i b u t i o n Johnston Is land: One poss ib l e record e x i s t s . Sundel l , a POBSP employee, wrote i n h i s f i e l d no te s 22 November 1963: "While on Johnston i n the evening I talked with an engineer who claims t o have seen a Black-footed Albat ross over t h e i s l a n d on November 1.7." No f u r t h e r confirmation of t h i s record was obta ined . Sand Is land: The only breeding record f o r t h e a t o l l was a s i g h t record made by a member of Wetmore's 1923 par ty : "W.G. Anderson, of our p a r t y , who had come i n November 1922, a s navigator f o r a f i s h i n g sampan, informed me he saw one, with i t s egg, on t h e beach of Sand Is land . None were present during our work i n J u l y 1923" (Wetmore, m s . b) . One recent s i g h t record i s ques t ionable . On 11 March 1964 a Black-footed Albat ross followed the USS ENERGY t o wi th in about 2.5 mi les of Sand Is land and departed j u s t a f t e r a harbor tug came t o a s s i s t t h e s h i p t o p o r t . Bra t l ey , a POBSP employee who was on Sand a t t h e time, repor ted i n h i s f i e l d notes: "I could see t h e Energy a t t h i s time from Sand, but I could not s ee i f t h e r e was any b i rd following it." On 12 March, Coast Guardsmen described t o Bra t ley a b i r d seen s i t t i n g on t h e causeway of Sand and f ly ing around over Johnston t h a t may have been t h e Black-footed Albat ross t h a t had followed t h e sh ip i n t h e day before. No f u r t h e r confirmation could be made of t h i s record. Populat ions The occurrence of a l b a t r o s s on Johnston A t o l l i n t h e p a s t i s poorly recorded. During t h e 1800's t h e r e were no s c i e n t i f i c v i s i t s and no known observa t ions r e l i a b l e enough t o determine the spec ie s composi- t i o n of t h e a t o l l ' s avifauna. Brooke (ms.) reported "an a lba t ros s" a s being c o l l e c t e d on 15 March 1859. A guano prospector , Le Grand Brown, l i s t e d " the Gooney" a s being p resen t i n 1905 (U.S. Nat. Archives, R.G. 59, guano l e t t e r s ) , but no q u a n t i t a t i v e s ign i f i cance can be a t tached t o t h i s record . I n add i t ion t o Anderson's breeding s i g h t record i n November 1922 (Wetmore, m s . b ) , he (Anderson, 1954) repor ted seeing a Black-footed Albat ross t h e r e i n 1929, but t h i s may have been an erroneous l i s t i n g of the b i rd he saw i n 1922. Rice and Kenyon (1962) in t e rp re t ed Wetmore's observa t ions , including t h e absence of a l b a t r o s s bones i n t h e p i l e s of bones l e f t by f ea the r hunters s h o r t l y before Wetmore's v i s i t , a s evidence t h a t a l b a t r o s s were ex t i rpa t ed [ p r i o r t o t h e time of s a id f e a t h e r hun te r s ] . It i s equal ly ' l i k e l y t h a t t h e a l b a t r o s s populat ion never exceeded a f e w b i r d s , even before t h e f i r s t f ea the r poachers a r r i v e d . Johnston A t o l l i s the southernmost known breeding i s l and fo r Black-footed Albat ross , un le s s the record (Rice and Kenyon, 1962) f o r Taongi A t o l l (14"35'N) i n t h e northern Marshal ls is v a l i d . Amerson (1969), however, found no evidence t o s u b s t a n t i a t e t h i s Taongi breeding record . An e l d e r l y Polynesian cons t ruc t ion worker on t h e i s l a n d s i n t h e l a t e 1930's t o ld Amerson of t h e POBSP i n 1964 t h a t a l b a t r o s s e s of both spec ies were on t h e i s l and when cons t ruc t ion work began, and t h a t they were sho t by marines. Whether they were shot f o r lack of b e t t e r enter tainment , or whether the re was an o f f i c i a l e f f o r t t o r i d the i s l a n d s of these b i r d s because of t h e hazard t o a i r c r a f t , i s not known. An a r t i c l e i n t h e New Yorlcer magazine (Anon., 1945) l i s t e d t h e Black-footed Albat ross a s occurr ing on Johnston A t o l l , but t h i s l i s t i n g was "based i n p a r t on the B r i t i s h Admiralty Sa i l ing Direc t ions , and i n p a r t on information supplied by U.S. Navy personnel who had been s t a t ioned on t h e i s l a n d ....'I (Hutchinson, 1950: 186), and i s of l i t t l e value i n determining t h e s t a t u s of t h e s p e c i e s on t h e a t o l l . Even i f man l e f t Johnston A t o l l i t i s doub t fu l i f Black-footed Albat ross would r e t u r n t o i t s i s l a n d s to breed because of t h e i r s t rong tendency t o n e s t on t h e i r p lace of hatching. Those t h a t may have survived t h e f e a t h e r hun te r s and e a r l y m i l i t a r y cons t ruc t ion have probably long s ince gone elsewhere, or m q s t l i k e l y have d ied . Annual Cycle The s i g h t record of an egg i n November 1922 by Anderson (Wetmore, m s . b) f a l l s wi th in t h i s spec ie s ' breeding c y c l e i n t h e northwestern Hawaiian Is lands . There, a d u l t s a r r i v e dur ing t h e l a s t p a r t of October, eggs a r e l a i d about mid-November, young hatch beginning l a t e January, and a d u l t s and young leave by t h e end of J u l y (Richardson, 1957). Banding and I n t e r i s l a n d Movement No Black-footed Albat ross were banded and no specimens were co l l ec t ed from t h e i s l and by POBSP personnel . No i n t e r i s l a n d movements a r e known. At-Sea D i s t r i b u t i o n Brooke (ms.) saw "a black a lba t ros s" on 19 March 1859 while s a i l i n g west two days from Johnston Ato l l . Black-footed Albat ross do occur a t s ea i n the g r i d southwest of Johnston A t o l l , where they have been found i n small numbers from December through A p r i l (POBSP, 1967a). The POBSP co l l ec t ed t h r e e specimens a t sea near Johnston A t o l l (Appendix Table 7 ) . They a r e seldom found below 1 O o N i n the c e n t r a l P a c i f i c (King, 1967). LAYSAN ALBATROSS Diomedia imutabitis Sta tus Former uncommon breeding spec ie s , p re sen t ly a r a r e v i s i t o r ; a r egu la r but r a r e winter v i s i t o r a t sea near Johnston A t o l l . Small numbers nested on Johnston Is land p r i o r t o t n i l i t a r y occupancy. Ecological D i s t r i b u t i o n Johnston I s l and : Wetmore (ms. b) recorded one young b i rd on the high barren a r e a s of Johnston Is land i n J u l y 1923. None was observed i n l a t e A p r i l or May 1928 by Thurston (1928), a l though t h i s spec ies may have been present i n the l a t e 1930's ( see Blaclc-footed Albat ross account) . A few v i s i t e d here i n 1949, probably November or December (Jensen, 1949). Three were present i n e a r l y winter 1957 (Manandic, pe r s . comrn.). Manandic, former SSgt . , USAF, s t a t ioned on Johnston i n 1957, knew t h e b i r d s of t h e a t o l l q u i t e we l l and used the term "a lba t ross" not 1 , gooney" t o desc r ibe t h e b i r d s i n quest ion. He described them a s l a r g e white b i r d s , with hooked beaks, a desc r ip t ion t h a t could hard ly have f i t any other spec ies . Sand Is land: One a d u l t with a ba re brood patch landed on t h e road t o t h e t r a n s m i t t e r bu i ld ing on 1 0 December 1965. It was banded, photographed, and e c t o p a r a s i t e s c o l l e c t e d before being r e l eased by POBSP personnel. Another a d u l t was seen soaring over t h e western po r t ion of Sand f o r a t l e a s t t e n minutes on 26 December 1966 by POBSP personnel. Populat ions For the Laysan Albat ross , a s f o r t h e Black-footed Albat ross , Johnston A t o l l was previous ly t h e southernmost extreme of t h e breeding range. Small numbers bred on t h e a t o l l p r io r to m i l i t a r y occupancy, but now t h e spec ie s is a r a r e v i s i t o r . The d iscuss ion of t h e occurrence of a l b a t r o s s e s before 1923, and of Rice and Kenyon's (1962) i n t e r p r e t a t i o n s of Wetmore's observa t ions , a r e included i n t h e Black-footed Albat ross account and apply equal ly to t h e Laysan Albat ross . It i s a l s o u n l i k e l y t h a t t h i s spec ie s w i l l r e t u r n t o Johnston A t o l l t o breed, even i f man dec ides t o abandon t h e a t o l l i n the f u t u r e . Annual Cycle Wetmore (ms. b) wrote of t h e one young b i r d , nea r ly ready t o f l y i n J u l y 1923, a s : "This should not be taken a s i n d i c a t i v e of t h e r a r i t y of the spec ie s , s i n c e by July--most inembers of t h i s spec ie s had l e f t t h e i r breeding grounds [ i n t h e northwestern Hawaiian I s l a n d s ] , and were a t sea." The annual cyc le of t h e Laysan Albat ross i n t h e Hawaiians i s s imi l a r t o t h a t described f o r t h e Black-footed Albat ross , but the c y c l e i s about two weeks l a t e r (Richardson, 1957). Banding and I n t e r i s l a n d Movement The only Laysan Albat ross banded by POBSP personnel on t h e a t o l l , an a d u l t banded on Sand 10 December 1965, was seen and i d e n t i f i e d by i ts orange, p l a s t i c , leg-streamer over Kure A t o l l , nea r ly 1,000 miles t o t h e northwest, t h r e e days l a t e r , 13 December, by POBSP personnel (Woodward, 1972). At-Sea Dis t r ibugion Laysan Albat ross have been observed only during one month-- February--in t h e g r i d southwest of Johnston A t o l l (POBSP, 1967a). This spec ie s seldom i s found below 15'73 i n the c e n t r a l P a c i f i c (King, 1967). PHOENIX PETREL Pterodroma aZba S t a t u s Accidental ; one specimen reccrd from Sand I s l a n d . Observations The only Phoenix P e t r e l recorded from Johnston A t o l l was an a d u l t female Kepler and Lehner c o l l e c t e d a f t e r i t landed " in a TribuZus bush i n t h e Wedge-tailed Shearwater colony ..." on 18 September 1964. The b i rd appeared t o be i n good h e a l t h and was kept a l i v e f o r a few days before i t was k i l l e d and preserved. Phoenix P e t r e l s breed i n t h e summer i n t h e Line and Phoenix I s l a n d s (Clapp, pers . comm.) and occur south t o about 24's l a t i t u d e i n t h e c e n t r a l P a c i f i c (Efurphy and Pennoyer, 1952). Small numbers occur a t sea nor th t o t h e Hawaiian I s l ands (King, 1967) but may only r a r e l y a l i g h t on i s l a n d s i n t h i s a r e a . POBSP (1967a) personnel recorded Phoenix P e t r e l s a t sea i n low numbers i n t h e g r i d southwest of Johnston A t o l l only during October, November, January, and February. Specimens The Phoenix P e t r e l noted above i s a new specimen record f o r Johnston Ato l l . Furthermore, i t has never been recorded on land i n t h e Hawaiian Is lands . BULWER'S PETREL Butweria bulwerii S t a t u s Uncommon breeding spec ie s , present from March t o e a r l y September. Nests i n rock c rev ices along t h e causeway, on t h e e a s t and west shores , and on t h e southwest i s l e t of Sand I s l and ; previously nested on Johnston I s l and . About half of t h e 40 t o 50 a d u l t s t h a t r e t u r n each year at tempt t o breed, and a t l e a s t f i v e t o t e n young a r e produced yea r ly . Adults r e t u r n i n March, l a y i n May or June, and depar t j u s t ahead of t h e chicks which hatch i n l a t e June o r e a r l y J u l y and f l edge i n l a t e August or e a r l y September. Nests a r e i n rock c rev ices mainly along t h e man-made causeway of Sand I s l a n d . Ecological D i s t r i b u t i o n Johnston Is land: Wetmore (ms. b) i n J u l y 1923 found about 400 nes t ing i n c revices i n t h e rock ledges of Johnston Is land with young ranging from a week old t o those p a r t l y covered with contour f e a t h e r s . Wetmore's f i e l d notes (ms. a ) r e v e a l something of t h e i r h a b i t s and h a b i t a t s : Common, n e s t i n g i n t h e r o c k l e d g e s a l o n g t h e beach where I h e a r t h e i r b a r k i n g c a l l s day and n i g h t . They a r e more advanced i n t h e i r b r e e d i n g h e r e t h a n f a r t h e r n o r t h a s they have young from a week o l d t o t h o s e growing con tour f e a t h e r s . The s m a l l young a r e a s u s u a l i n p e t r e l s v e r y f l u f f y w i t h heavy down abou t t h e head t h a t a lmos t h i d e s t h e eyes . Young beg inn ing t o m o l t i n t o f i r s t plumage appear much l a r g e r than t h e a d u l t and i n r e a l i t y a r e h e a v i e r because of t h e heavy l a y e r of g r e a s y f a t t h a t c o v e r s t h e e n t i r e body. They remain h idden i n t h e l e d g e s d u r i n g t h e day , b u t a t n i g h t come o u t i n t o t h e open s h u f f l i n g abou t on t h e b r e a s t . A t day t h e y s e e k s h e l t e r when exposed t o l i g h t . The l a r g e r o n e s r e s e n t h a n d l i n g and a t t e m p t t o b i t e a s do a d u l t s when handled a t t h i s season . The young u t t e r a low w l l i s t l i n g wheeze somewhat s i m i l a r t o t h e n o t e of a squab. A d u l t s d e l i g h t t o rest a few i n c h e s a p a r t and w i t h ex- t ended head and s w e l l i n g t h r o a t u t t e r t h e i r comical l i t t l e b a r k i n g c a l l , a n o t e common t o b o t h s e x e s . When q u i e t t h e y r e s t p r o s t r a t e on t h e b r e a s t and moving merely s h u f f l e a long b a r e l y r a i s i n g t h e body f r e e of t h e sand and dropping back a t once. About 400 on Johns ton I s l a n d . None b a s been recorded on. J o h n s t o n I s l a n d s i n c e , most :Likely because t h e n a t u r a l r o c k c r e v i c e s where Wetmore found them i n 1923 have a l l been d e s t r o y e d by m i l i t a r y a c t i v i t i e s . Sand I s l a n d : Wetmore (ms, b ) saw none on Sand i n Judy 1923. Eecause of t h e i r n o c t u r n a l and s e c r e t i v e h a b i t s , Bulwer ' s P e t r e l s were comp:l.etely over looked by POBSP p e r s o n n e l i n 1963 b u t were , hoirever, r e - corded as n e s t i n g from 1964 t o 1969, Bu lwer ' s P e t r e l - s were seldoiil found excep t i n t i le rock c r e v i c e s where they n e s t e d ( F i g s . 45 and 46 ) . The d i s t r i b u t i o n of t h e s e s i t e s i s shown i.n F i g u r e 4 7 . Host n e s t s were a l o n g t h e causeway, where a n g u l a r r o c k s and b l o c k s of c o n c r e t e form deep c r e v i c e s i n which t h e b i r d s l ~ a y t h e i r eggs on a t h i n mat of g r a s s s tems. T h e r e were a l s o a F e w s i t e s under chunks of c o n c r e t e on t h e e a s t and wes t s h o r e s of t h e o r ig ina l . p o r t i o n of t h e i s l a n d , some of t h e same ones used by Chr i s tmas Shearwaters . The s i z e s of c a v i t i e s r e q u i r e d by t h e s e two s p e c i e s appear t o be s u f f i c i e n t l y d j - f f e r e n t t o p r e v e n t c o m p e t i t i o n between t h e n f o r s i t e s . 011 t h e s o u t h - west i s l e t a b i r d was hea rd cal l . ing i n 1967 b u t cou ld n o t be reached o r s e e n i n t h e c r e v i c e s , severa1 ' :Eeet d e e p , between c o n c r e t e chunks used t o b u i l d t h e bunker . I n 1969 a c h i c k a l m o s t r eady t o f l e d g e was caugh t t h e r e . Nes t ing p robab ly occur red t h e r e i n o t h e r y e a r s a s w e l l . I n 1967 one b i r d was found among r o c k s al.ong t h e s o u t h s h o r e , b u t no n e s t s were e v e r d i s c o v e r e d t h e r e . Figure 45. Bulwer's P e t r e l ch ick , about 2 months o l d , i n f r o n t of rock c rev ice n e s t s i t e along causeway, Sand I s l and , Johnston A t o l l , 25 August 1966 (POBSP photo by P, C. Shelton) . Figure 46. Concrete s l a b s on e a s t shore, a t base of no r theas t peninsula , Sand I s l a n d , Johnston A t o l l , 8 May 1967. Christmas Shearwaters nes ted r e g u l a r l y under t h e l a r g e s l a b s a t l e f t , and Bulwer's P e t r e l s attempted t o n e s t a t l e a s t once under t h e s l a b s i n cen te r of photo. Brown Noddies nested i n t h e edge of the Sesuvium growing j u s t above t h e storm beach (POBSP photo by P . C . She l ton) . 0 Birds Found, No N e s t Figure 47. Distribution of Bulwer's Petrel nest sites, Sand Island, Johnston Atoll, 1964-1969. Rarely were Bulwer's P e t r e l s found i n t h e open, away from rocky cover. One of t h e 1965 chicks t h a t returned i n 1969 was f i r s t found s i t t i n g i n t h e road on t h e causeway but i t was found l a t e r i n 1969 i n a c a v i t y on t h e causeway. On 3 August 1966 a lone c a l l i n g b i r d wi th a ba re brood patch was found on open ground nor th of t h e t r ansmi t t e r bui ld- ing among Sooty Terns. Almost exac t ly t h r e e years l a t e r , 2 August 1969, t h e same b i r d appeared i n t h e same p lace , aga in s i t t i n g a lone among Sooty Terns and c a l l i n g . Poss ib ly t h i s b i r d was hatched, or had formerly nes ted , a t a now destroyed s i t e under a rock on concre te s l a b near where i t ap- peared i n these two yea r s . Populat ions These nocturna l and s e c r e t i v e p e t r e l s a r e among t h e most d i f f i c u l t t o census of t h e l e s s common b i r d s using t h e i s l and . They were completely overlooked i n 1963. Semimonthly es t imates by d i f f e r e n t observers v a r i e d , r e s u l t i n g i n a wide spread i n t h e ranges f o r es t imates shown i n Figure 48. The mean of these e s t ima tes f o r each period probably r ep resen t s t h e t r u e numbers f a i r l y w e l l , a l though t h e spring buildup may be s teeper than shown. A d u l t s 70 r. . . - e . Means Figure 48. Means and extremes of semimonthly es t imates of Bulruer's P e t r e l numbers, Sand I s l and , Johnston A t o l l , 1964-1969. The number of a d u l t s handled each year probably r ep resen t s 75 t o 90 percent of t h e r e tu rn ing b i r d s on average, although i t may have been no more than 50 percent i n 1966. The upward t rend i n numbers handled each year a t l e a s t p a r t l y r e s u l t e d from an inc rease i n b i rds present and was not e n t i r e l y due t o increased e f f o r t t o ca t ch them. I f one makes the reasonable assumption t h a t Wetmore's 1923 v i s u a l e s t ima te of 400 Bulwer's P e t r e l s was s l i g h t l y low, t h i s spec ie s has been reduced by perhaps 90 percent s i n c e 1923. The na tu ra l rock c rev ices on Johnston I s l and where Netmore found t h e s e b i rds i n 1923 have a l l been destroyed. The b i rds using t h e a t o l l now depend completely upon t h e c rev ices on Sand I s l and between rocks and chunks of concre te used t o bu i ld t h e causeway, and on space under s l a b s of concre te sca t t e red around t h e i s l and . A s i n t h e case of Christmas Shearwaters, i t i s d i f f i c u l t t o s e e where any Bulwer's P e t r e l s would have been a b l e t o nes t during t h e years of in- t e n s i v e m i l i t a r y use of t h e two i s l a n d s , and i t i s l i k e l y t h a t during s e v e r a l years t h e r e was no success fu l nes t ing . Under present condi t ions t h e r e probably a r e more a v a i l a b l e n e s t s i t e s than a r e being used , and b a r r i n g f u r t h e r d is turbance the population should be a b l e t o inc rease t o some e x t e n t . Production of chicks was r e l a t i v e l y high f o r t h i s spec ies and ap- peared t o be increas ing from 1964 through 19G9 (Table 28). Losses were mainly of eggs r a t h e r than chicks , and most l o s s e s were a t t r i b u t e d t o f looding by high t i d e s . I f t h e a d u l t populat ion was about 50 i n 1968 and 1969, then t h e number of ch icks produced was about 20 percent of t h i s number. Mor ta l i t y r a t e s f o r a d u l t s a r e unknown, but t h e apparent i nc rease i n t o t a l numbers i n d i c a t e s t h a t t h e r e must be a n e t ga in from year t o year --more chicks a r e produced than a d u l t s l o s t . I n 1968 the f i r s t known-age chicks re turned t o t h e island--the s i n g l e chick banded i n 1964 and one banded i n 1965. Neither of t hese was recaptured i n 1969, but t h r e e more of t h e s i x 1965 b i r d s returned i n 1969. Thus of seven cliiclcs banded i n 1964 and 1965, f i v e survived long enough t o r e t u r n t o t h e i s l a n d , one a t age t h r e e years and t h e o the r s a t four . None of these known-age b i r d s was known t o breed, but two of t h e 1965 chicks t h a t returned i n 1969 developed bare brood patches and engaged i n cour tsh ip c a l l i n g . A l l r e - turned i n l a t e May or l a t e r , a t l e a s t two months a f t e r e s t ab l i shed breeders r e t u r n , and a l l returned t o approximately t h e same sec t ion of t h e i s l a n d where they had hatched. Annual Cycle Table 29 shows t h e a v a i l a b l e d a t e s of major events i n t h e annual cyc le of Bulwer's P e t r e l s on Sand Is land dur ing POBSP s tud ie s . Because t h e b i r d s a r e s e c r e t i v e , r e tu rn ing t o t h e i s l and a t dusk or a f t e r dark , and a l s o re- t u rn ing a t t h e time Sooty Terns a r e most abundant and most demanding of research time, observat ions were not a s complete a s f o r the more conspicu- ous spec ies . Exact d a t e of lay ing was n o t determined f o r any eggs, although d a t e s of hatching and f ledging were known f o r s eve ra l . Table 28. P roduc t iv i ty of Bulwer's P e t r e l s on Sand I s l and , Johnston A t o l l , 1964-1969" Chicks Hatched Fledged Percent Percent of Year Eggs No. Percent No. of eggs hatching 1969 15 10 67 10 67 100 T o t a l s 71 53 67 45 64 85 " A l l egg and chick f i g u r e s a r e minima, considered t o be about 90 Dercent complete [and t h e number of a d u l t s handled r ep resen t s about 90 percent of t h e t o t a l ] . Bulwer's P e t r e l s were completely absent from t h e a t o l l f o r about s i x months, from l a t e September t o l a t e March. The f i r s t b i r d s probably re- turned t o t h e i s l and each year i n t h e l a s t week of March (see Figs . 37 and 48), a l though i n some years none was seen u n t i l nea r ly mid-April. On a r r i v a l they come i n a t about dark and cour t i n the n e s t s i t e s through t h e n i g h t , l eaving sometime i n t h e e a r l y morning. They a r e most e a s i l y found a t t h i s time, f o r t h e i r cour t ing c a l l s can be e a s i l y heard. Many n e s t c a v i t i e s a r e too deep f o r an observer t o reach t h e b i r d s , or i n some cases even t o s e e them, but a t t h i s season they can be c a l l e d out r e a d i l y by imi t a t ing t h e i r cour t ing c a l l s . F i r s t eggs were found usua l ly by the end of May, but i t i s l i k e l y t h a t l ay ing began by mid-May i n most years . The l a t e s t known laying was about 5 J u l y 1969. This egg, and t h e l a t e s t l a i d i n other yea r s , d id not ha tch , and probably was produced by young a d u l t s , l ay ing f o r t h e f i r s t time. Exact incubat ion per iods were not determined, but two 1968 eggs required a t l e a s t 44 and 47 days. E a r l i e s t chicks appeared i n l a t e June and none was known t o hatch a f t e r mid-July. The da ta a r e insuf - f i c i e n t t o draw d e f i n i t e conclusions, but apparent ly the success fu l n e s t e r s a r e c l o s e l y synchronized. Egg l ay ing may extend over s i x or seven weeks, but t h e l a t e s t eggs never su rv ive ; thus a l l t h e chicks hatch within about t h r e e weeks of each o the r . T a b l e 29. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Bu lwer ' s P e t r e l s on Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969" Year A d u l t s p r e s e n t Laying Ha tch ing F l e d g i n g 1964 3 0 M a r . - l a t e S e p t . by 20 Nay-? ca. 1 0 Ju ly -? ? - l a t e S e p t . 1965 20 Mar.-ca. 1 0 S e p t . by mid-May-? l a t e June-ea r ly J u l y ca. 3 0 Aug.-ca. 1 5 S e p t . 1966 11 Apr.-ca. 26 Aug. l a t e May-? e a r l y J u l y ca. 3 0 Aug.-9 Sep t . 1967 7 Apr. - l a t e Aug . by 1 5 May-? ?-? l a t e Aug.-mid-Sept. 1968 11 Apr . -ea r ly Sep t . l a t e May-mid-June ca. 1-15 J u l y ca. 1-18 S e p t . 1969 25 Mar.-ca. 3 0 Aug. by 1 5 Xay-ca. 5 J u l y by 29 June-5 J u l y ca. 26 Aug.-6 S e p t . " P r e c i s e l y known d a t e s a r e u n d e r l i n e d ; o t h e r s a r e e a r l i e s t o r l a t e s t observed o r e s t i m a t e d . Fledging took p lace from t h e l a s t week of Augu'st through mid- September. The period from hatching t o f l edg ing , determined f o r e igh t 1968 and 1969 b i r d s , ranged from 57 t o 67 days (mean = 62 days) . Af ter t h e eggs were l a i d only one a d u l t was found a t a t ime a t t h e n e s t , and a f t e r hatching t h e ch icks were guarded only f o r t h e f i r s t few days. Nearly a l l five-day-old b i r d s measured i n 1969 were unattended, even a t n ight . Apparently t h e deep, well-protected n e s t s i t e s make p a r e n t a l p r o t e c t i o n unnecessary and t h e a d u l t s s t a y only long enough t o feed t h e i r ch icks , then immediately r e t u r n t o sea. P a i r s and s i n g l e b i r d s without eggs continued t o r e t u r n t o t h e n e s t s i t e s and cour t through e a r l y August when o the r b i r d s were incubat ing or feeding chicks. L a t e s t c a l l i n g was heard 1 4 August i n 1969. By t h e time t h e chicks a r e ready t o f l e d g e a l l a d u l t s a r e very sca rce ; not only do t h e non-breeders cease t o come back but those with chicks abandon t h e i r o f f sp r ing f o r s e v e r a l days before they f ledge . No a d u l t s have been recorded a f t e r mid-September, and i n most years none was found a f t e r t h e end of August. Molt probably occurs e n t i r e l y while t h e b i r d s a r e away from t h e i s l a n d . Only a few b i r d s were examined c a r e f u l l y f o r mol t , but a l l those examined i n e a r l y spr ing had completely new plumage and none examined l a t e i n t h e breeding season had begun t o molt. Specimens Appendix Table 7 l i s t s t h e t e n specimens of Bulwer's P e t r e l col- l e c t e d from Johnston A t o l l . Wetmore co l l ec t ed n ine (sk ins : 5 male, 4 female) and POBSP personnel co l l ec t ed one (sk in : 1 male) i n 1964; a l l a r e housed i n t h e USNM. This i s considered a s a new specimen record , a s we l l a s a new breeding record . Banding and Movements Tables 24 and 30 show banding and r ecap tu re e f f o r t s on Bulwer's P e t r e l s . These b i r d s do not d i g and consequently band wear was much l e s s than on shearwaters . Th i r t een of t h e 22 a d u l t s banded i n 1964 were re - captured i n 1969 and a l l bands were l e g i b l e and i n no immediate danger of being l o s t . None was rebanded. A few b i rds may have changed mates or taken new ones when t h e former mate was l o s t , and a few b i r d s changed nes t s i t e s , bu t gene ra l ly pa i r and s i t e bonds appeared t o be very s t rong. Members of a t l e a s t two p a i r s stayed together from 1964 through 1969, one p a i r d e f i n i t e l y using t h e same n e s t s i t e each year and t h e other us ing t h e same or another c l o s e by. No i n t e r i s l a n d movements of Bulwer's P e t r e l s t o or from Johnston A t o l l a r e known. At-Sea Di s t r ibu t ion Bulwer's P e t r e l s were found i n t h e g r id i n a l l months except December, January, February, and June (Table 21 and Fig. 4 9 ) . Since t h e g r id populat ion i s too high t o be accounted f o r by Johnston b i r d s , and t h e peaks occur j u s t b e f o r e and a f t e r t h e breeding season, i t i s u n l i k e l y t h a t Johnston based b i r d s make more than a minor con t r ibu t ion t o t h e g r i d populat ion. The September peak i n g r id b i r d s i s c e r t a i n l y concurrent with t h e major southward migrat ion from t h e Hawaiian cha in (POBSP, 1967a). F igure 49. Diurnal occurrence of Bulwer's P e t r e l s a t s ea 175 m i of Johnston A t o l l , 1963-1967. southwest Table 30. Banding and recaptures of Bulwer's P e t r e l s , Sand I s l a n d , Johnston A t o l l , 1964-1969 Adults handled New Young Tota l new Year bandings Returns* T o t a l banded band ings 1964 22 0 2 2 1 23 *Each b i r d counted only once each year recaptured . WEDGE-TAILED SHEARWATER Puffinus pacifieus Sta tus Abundant breeding spec ie s , present from March t o e a r l y December. Nests i n shallow t o deep burrows, mainly i n dense Lepturus on t h e west half of t h e o r i g i n a l po r t ion of Sand I s l a n d ; a few nes t on Johnston I s l and . Ranks t h i r d behind Sooty Terns and Brown Noddies i n number of young produced each year (300 t o 450), and f o u r t h behind these two spec ie s and Red-footed Boobies i n number of a d u l t s us ing t h e i s l and (3,000). Af ter an absence of about t h r e e months, a d u l t s r e t u r n i n March and immediately begin cour t sh ip and burrow digging, mainly i n dense Lepturus on t h e west half of the o r i g i n a l po r t ion of Sand I s l and . Eggs a r e l a i d i n l a t e June and e a r l y J u l y and most ch icks hatch during t h e l a s t t h r e e weeks of August. Fledg- ing begins i n November and t h e l a s t ch icks and a d u l t s usua l ly leave i n e a r l y December. Ecological D i s t r i b u t i o n Johnston Is land: Brooke (ms.) described what most l i k e l y were Fledge-tailed Shearwaters from Johnston I s l and on 15 March 1859, a s fol lows. The ground i s undermined by p e t r e l s who l i v e two toge the r , and i n walking over t h e i s l and I came ac ross many p a i r s si t- t i n g o r l y ing coz i ly together a t t h e en t rance of t h e i r r e t r e a t s , basking i n t h e Sun and screened from t h e wind by t h e g ras s . They were q u i t e noisy and many were b i l l i n g and cooing. The people onshore c a l l them diggers from t h e f a c t of t h e i r l i v i n g i n holes . I f these were Wedge-tailed Shearwaters--there a r e no records of Bonin P e t r e l s from Johnston Atol l - - the i r breeding cycle then was not i n t h e same season a s today. Wetmore (ms. a and b) noted l a r g e numbers of Wedge-tailed Shearwaters on Johnston I s l and i n J u l y 1923. The i s l a n d was honey-combed with burrows. Most were incubat ing i n burrows up t o four f e e t long; o the r s were under l i t t l e mats of vege ta t ion above ground. Various o ther v i s i t o r s noted t h i s spec ie s on t h e i s l a n d , including Thurston (1928) i n Apr i l 1928, Clark (1945 a and b) i n May 1945, and Fennel1 (1948) i n 1948. POBSP personnel recorded a few wedge-tails each year during 1963-1969. Johnston I s l a n d , where most of t h e o r i g i n a l b i r d s nes ted , probably became l e s s su i t ed t o them throughout t h e war years . From 1963 t o 1969 a few wedge-tails were a t r r a c t e d t o t h e f a i r l y dense s tand of Vi ter t r i f o t i a , growing i n loose g rave l ly sand on a poin t between t h e main s t r e e t (Arthur Avenue) and t h e e a s t taxiway. They dug shallow burrows t h e r e , or simply s a t o n t h e ground under the bushes; a few eggs were l a i d some yea r s but no young were known t o f l edge . A few b i r d s a l s o used t h e crawl space under a t l e a s t one bui ld ing and burrowed under concre te s l a b s on top of an underground bui ld ing . Sand I s l and : Wetmore (ms. a and b) recorded t h i s spec ies on Sand i n J u l y 1923. He, a s d id Thurston (1928) i n A p r i l 1928, noted t h e s o i l on t h e i s l and was honey-combed with shearwater burrows. Moynihan (1957) found a t l e a s t a few on t h e o r i g i n a l p a r t of Sand s i t t i n g on t h e ground i n t h e open o r j u s t i n s i d e t h e mouths of t h e i r burrows during t h e daytime i n A p r i l 1957. POBSP personnel recorded t h i s spec ie s a s very numerous on t h e o r i g i n a l po r t ion from 1963 through 1969. Amerson recorded them with almost f ledged young i n November 1973. F igures 35, 43 and 50 show t h e d i s t r i b u t i o n of Wedge-tailed Shearwaters on Sand I s l and . The prefer red h a b i t a t from 1963 t o 1973 was deep sand, s t a b i l i z e d by dense, undisturbed Leptmus, which was prominent only on t h e west ha l f of t h e o r i g i n a l po r t ion (Figs. 5 1 and 52) . Many burrows were dug i n more open sandy a r e a s , but without g r a s s r o o t s t o hold the loose sand, heavy r a i n s caused many of these burrows to cave i n . They a l s o burrowed under sidewalks around t h e t r ansmi t t e r bui ld ing and t h e abandoned gun emplacement. The man-made end of Sand Is land was too g rave l ly and hard-packed f o r the b i r d s t o burrow, but Ptuchea caroZinensis bushes growing southeas t of t h e bar racks were t h i c k enough by 1969 t o a t t r a c t a t l e a s t one b i r d f o r long enough t o l a y an egg. The necessary element i n a l l t hese h a b i t a t s was s h e l t e r from t h e sun. I Where t h i s was o b t a ~ n e d without digging, a s i n t h e gun emplacement o r under bui ld ings , t h e b i r d s made no attempt t o d i g , but simply l a i d t h e i r eggs on t h e ground i n a shallow cup formed of b i t s of g r a s s , bones, and f e a t h e r s . Burrows were l i ned s i m i l a r l y . 0 100 200 I Feet Figure 50. D i s t r i b u t i o n of Wedge-tailed Shearwater n e s t s i t e s on Sand I s l and , Johnston A t o l l , 1963-1969. Numbers i n d i c a t e ch icks banded i n 1968. Populat ions The Wedge-tailed Shearwater populat ion a t Johnston A t o l l c o n s i s t s predominantly of l i g h t phase indiv iduals . Light phase populat ions a l s o breed i n t h e Hawaiian I s l a n d s and t h e nor thern Marshal l I s l ands . Figure 53 shows means and extremes of semimonthly es t imates made by POBSP personnel from 1964 through 1969 of Wedge-tailed Shearwater numbers on Sand Is land . These es t imates were u s u a l l y based on sample counts of b i r d s above ground, p lus a l i b e r a l allowance f o r b i r d s i n burrows and b i r d s not r e tu rn ing t o t h e i s l and each n igh t . Year t o year v a r i a t i o n s i n these e s t ima tes were small and more l i k e l y r e s u l t e d from d i f f e r e n c e s i n es t imat ing techniques than r e a l v a r i a t i o n s i n shearwater numbers. Hence, t h e r e i s no evidence t h a t t h e number of Wedge-tailed Shearwaters us ing t h e a t o l l v a r i e d during t h e yea r s of POBSP s t u d i e s . On 30 September 1966 Shel ton made a sample count on a l l p a r t s of Sand I s l and and found t h a t 57 percent of 150 Wedge-tails had f r e s h orange s treamers put on some time t h a t year . About 1,720 b i r d s had been streamered i n 1966, most of them i n August and September. Although t h e r e was no way to determine an exact f i g u r e , streamer l o s s e s were thought t o be l e s s than Figure 51. Wedge-tailed Shearwater ch ick i n f r o n t of burrow under L e p t u r u s r e p e n s clumps, Sand I s l a n d , Johnston A t o l l , 2 September 1966 (POBSP photo by P. C. She l ton) . ..a . '""~,~ *.._ , ,. M A- Figure 52. Wedge-tailed Shearwaters among TribuZus, Boerhavia, and Lepturus on s o u t h ~ e s t Sand I s l and , Johnston A t o l l , mid- morning J u l y 1963 (POBSP photo by A . B . Amerson, J r . ) . J F M A M J J 9 , F 0 N D F i g u r e 53. Means and e x t r e m e s o f semimonthly e s t i m a t e s of Wedge- ta i led S h e a r w a t e r numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1.969. t e n p e r c e n t by 30 September. I f t h e r e had been no s t r e a m e r l o s s , t h e n t h e 1 , 7 2 0 b i r d s would r e p r e s e n t a p p r o x i n a t e l y 57 p e r c e n t of t h e t o t a l p o p u l a t i o n u s i n g t h e i s l a n d d u r i n g t h a t p e r i o d : 1,72010.57 = ca. 3 , 0 0 0 I f t e n p e r c e n t of t h e s t r e a m e r s had been l o s t by 3 0 September , t h e n t h e t o t a l p o p u l a t i o n would have been: 1,55010.57 = ca. 2 , 7 0 0 . It i s acknowledged t h a t t h e assumpt ions u n d e r l y i n g t h e s e calcu1.a- t i o n s may no t be f u l l y m e t , b u t t h e d a t a a r e p r e s e n t e d a s t h e b e s t a v a i l - a b l e es t i .mate of wedge- ta i l numbers on Sand 1sl.and d u r i n g t h i s p e r i o d . These f i g u r e s a r e on ly a b o u t one- four th l a r g e r t h a n t h e mean of t h e se1n.i.-monthly e s t i m a t e s , which s u g g e s t s t h a t t h e s e e s t i m a t e s a r e a f a i r l y good approx imat ion of t h e numbers of wedge- ta i lk u s i n g t h e i.sl.and d u r i n g t h e p e r i o d s invo lved . o n l y compara t ive d a t a from pre-I'OBSP s o u r c e s a r e from Wetmore's 1.923 o b s e r v a t i o n s i n which be e s t i m a t e d 2,500 wedge- ta i lk on. J o h n s t o n I s l a n d and 500 on Sand. S u p e r f i c i a l comparison of t h e s e f i g u r e s w i t h POBSP e s t i m a t e s and c a l c u l a t i o n s would i n d i c a t e t h a t t h e p o p u l a t i o n of t h e a t o l l had n o t changed a p p r e c i a b l y , b u t t h a t t h e former p o p u l a t i o n on. J o h n s t o n I s l a n d had moved t o Sand. But Wetmore's f i g u r e i s a v i s u a l e s t i m a t e , niade over o n l y a ten-day s t a y , i n which Sand i s l a n d was n o t v i s i t e d a t n i g h t when maximum p o p u l a t i o n s would have occur red . V i s u a l e s t i m a t e s by t h e POBSP i n mid-Ju1.y averaged abou t 2 ,000 b i r d s , o r two- t h i r d s Wetmore's e s t i m a t e . Wetmore though t t h a t a q u a r t e r of t h e s e v e r a l thousand b i r d s h e found k i l l e d by f e a t h e r poachers were Wedge-tailed Shearwate r s . Thus , h i s e s t i m a t e of 3 ,000 must have been at l e a s t a thousand less t h a n t h e o r i g i n a l number. Both Wetmore and T h u r s t o n s t a t e d t h a t t h e e n t i r e s u r f a c e of b o t h i s l a n d s was burrowed by wedge- ta i l s . A t t h a t t i n l e a t l e a s t f i v e t imes a s much dense 1,epturus hab i . t a t was a v a i l . a b l e as d u r i n g t h e 1 9 6 0 ' s . If t h e pre-war d e n s i t y of burrows (and b i r d s ) was as g r e a t as t h e d e n s i t y d u r i n g t h e 1 9 6 0 1 s , t h e n t h e former p o p u l a t i o n may have been s e v e r a l t imes t h a t of t h e p r e s e n t . No compara t ive d e n s i t y d a t a e x i s t , b u t it i s l i k e l y t h a t many b i r d s from Johnston have crowded on t o Sand I s l a n d , re- s u l t i n g i n g r e a t e r d e n s i t y t h a n occur red on t h e u n d i s t r u b e d i . s lands . I n summary, t h e n , i t would appear t h a t t h e o r i g i n a l . p o p u l a t i o n of wedge- ta i l s w a s a t l e a s t 1 . 5 t i m e s t h a t of t h e p r e s e n t , and may have been two o r t h r e e t i m e s t h e 3 ,000 now though t t o u s e t h e a t o l l . Whatever may have been t h e magni tude of t h e d e c r e a s e i n p o p u l a t i o n between Wetmore's v i s i t and t h e 1 9 6 0 1 s , t h e c a u s e i s n o t d i f f i c u l t t o de te rmine . The o r i g i n a l p o r t i o n of Sand I s l a n d - - l e s s t h a n t e n ac res - - now h a s t h e o n l y s i g n i f i c a n t amount of n a t u r a l h a b i t a t f o r t h i s s p e c i e s . There p robab ly were abou t 50 a c r e s a v a i l a b l e t o them on t h e two i s l a n d s b e f o r e m i l i t a r y c o n s t r u c t i o n began. The a b i l i t y of t h e s e b i r d s t o crowd t o g e t h e r t o a d a p t t o a r t i f i c i a l h a b i t a t s , such as abandoned bunkers and c r a w l s p a c e under b u i l d i n g s , h a s n o t been g r e a t enough t o a l l o w them t o m a i n t a i n t h e i r o r i g i n a l numbers. It i s n o t l i k e l y t h a t enough w e d g e - t a i l s were k i l l e d , e i t h e r by f e a t h e r poachers o r m i l i t a r y p e r s o n n e l , t o lower permanent ly t h e popula- t i o n . Reduced n e s t i n g s u c c e s s d u r i n g e a r l y y e a r s of m i l i t a r y occupancy of t h e a t o l l p robab ly g r a d u a l l y lowered t h e p o p u l a t i o n t o i t s p r e s e n t level . . J o h n s t o n I s l a n d , where most of t h e b i r d s o r i g i n a l l y n e s t e d , p robab ly became less s u i t e d t o them th roughout t h e war y e a r s , b u t C l a r k ' s (1945) and Fenne l l ' s (1948) no te s i n d i c a t e t h a t more than t h e few dozen l a r g e l y unsuccessful n e s t e r s found t h e r e i n t h e 1960's were using Johnston u n t i l a t l e a s t t h e l a t e 1940's. During POBSP s t u d i e s t h e number of chicks produced each year averaged about t e n percent of t h e a d u l t populat ion (Table 31). Figures i n t h i s t a b l e probably r ep resen t a t l e a s t 90 percent of t h e chicks f ledged i n each year . Egg numbers were l e s s r e l i a b l e because many bur- rows were too deep to inspec t . The two egg f i g u r e s given a r e based on counts made over t h e e n t i r e i s l a n d , with t h e r a t i o of eggs t o burrows assumed t o be t h e same f o r t hose t h a t could not be inspected a s f o r t hose t h a t were examined. These counts were made i n J u l y o r August, a f t e r an undetermined number of eggs had a l r eady been l o s t . Table 31. P roduc t iv i ty of Wedge-tailed Shearwaters on Sand I s l and , Johnston A t o l l , 1963-1968 Percent of eggs r e s u l t i n g i n Year Eggs l a i d Chicks banded* fledged chicks *Number banded r e p r e s e n t s a t l e a s t 90 percent of number f ledged. **Early September count. None banded. ***No cobnts were made i n 1969. Numbers of eggs and chicks were est imated t o be approximately equal t o 1967 numbers. Egg and chick l o s s e s r e s u l t e d from s e v e r a l f a c t o r s . Each year s e v e r a l dozen eggs were l a i d on top of t h e ground where t h e r e was no p r o t e c t i o n f o r t h e incubat ing b i r d s . Some of these eggs were incubated f o r s eve ra l weeks, but a l l were abandoned be fo re they hatched. Eggs sometimes were broken i n t h e burrows, poss ib ly a s a r e s u l t of d i spu te s over ownership of t h e burrows. Both these egg l o s s e s could be a t t r i b u t e d t o crowded condi t ions . Wedge-tails normally burrow under dense Lepturus and t h e burrows a r e f a i r l y s t a b l e , even i n heavy r a i n s , because of t h e holding power of t h e g r a s s r o o t s , but much of Sand I s l and i s now well vegeta ted and burrows i n bare sand f r equen t ly cave i n during heavy l a t e summer r a i n s . I n 1966 a dry spr ing and summer coupled with d is turbance from machinery i n May when t h e LORAN-C t r ansmi t t e r tower was re-guyed and painted l e f t l i t t l e hea l thy vegeta t ion and wedge-tail ch ick l o s s e s during August and September r a i n s were g rea t e r t h a t year than any o the r . Dogs k i l l e d a t l e a s t 35 chicks i n 1963 and a t l e a s t 11 i n 1964. The main c u l p r i t , a Coast Guard dog named "Jeffroe," was too aged t o have much impact a f t e r t hose years al though he survived u n t i l l a t e 1968. Only a few chicks were k i l l e d by o t h e r dogs. Adult m o r t a l i t y was very low and must not have been more than t e n percent per year both on and away from t h e i s l a n d , s i n c e an annual chick production of about t h i s magnitude appeared t o maintain t h e populat ion. Annual Cycle Table 32 and Figure 37 shows inc lus ive d a t e s f o r t h e major events i n t h e annual cyc le of Wedge-tailed Shearwaters on Johnston Ato l l . The approximate numbers of a d u l t s , eggs, and chicks a r e shown on Figure 53. S t r i k i n g f e a t u r e s of t h e wedge- ta i l ' s cyc le a r e t h e uniformity from year t o year and t h e shor tness of t h e laying period. Among Johnston b i r d s , t h i s spec ies holds t h e record on both counts. Wetmore's comment t h a t most b i r d s were incubat ing i n mid-July 1923 i n d i c a t e s t h a t t h e breed- ing cyc le was t h e same then a s now. I n 1969, when egg l ay ing was delayed i n s e v e r a l o the r spec ie s , wedge-tai ls a r r ived on schedule. The unusual weather p a t t e r n thought t o be r e spons ib le f o r the d i s r u p t i o n of breeding. i n t h e o ther spec ie s occurred i n e a r l y t o mid-February and ended about t h r e e weeks before t h e wedge-tails re turned . Other spec ie s d i d not r e - ga in normal s t a t u s u n t i l a f t e r wedge-tails returned but wedge-tai ls , being t h e l a t e s t breeders on t h e a t o l l , apparent ly were not a t a vulnerable s t a g e i n t h e i r cyc le i n t h e few weeks p r i o r t o r e tu rn ing t o t h e i s l ands . The synchrony of egg l ay ing i n t h i s spec ies i s remarkable. V i r t u a l l y a l l t h e eggs appear t o be l a i d wi th in a month, and most i n t h e l a s t two weeks of June. Accurate d a t e s f o r l a s t egg laying a r e not a v a i l a b l e f o r most years , but i n 1969 t h e southwest i s l e t bunker was checked a t l e a s t every o the r day through June and e a r l y J u l y and a l l t h e 16 eggs were l a i d between 12 June and 1 J u l y . Also, about t h r e e dozen eggs l a i d on top of t h e ground where they could be seen r e a d i l y were l a i d between t h e s e d a t e s . Close synchrony of laying i n t h i s spec ie s r e s u l t s p a r t l y from l ack of re- l ay ing , which i s a l s o t r u e of t h e o the r two breeding p roce l l a r i i fo rms (Christmas Shearwaters and Bulwer's P e t r e l s ) . Lack of chose synchrony i n these two spec ie s may be r e l a t e d t o t h e i r occurr ing i n much smaller numbers than wedge-tails. Wedge-tails began cour tsh ip and burrow digging almost immediately on a r r i v i n g back on t h e i s l and each year . For t h e f i r s t few days a f t e r they re turned , they were present a t n igh t only, but soon small groups s tayed through a t l e a s t p a r t of t h e day. Night numbers were always a t l e a s t twice t h e daytime numbers. Numbers increased through l a t e March and Apr i l , reaching a maximum i n May when cour tsh ip was most i n t ense and copula t ion occurred. The d i p i n e a r l y June (Fig. 49) r e s u l t e d from females s tay ing a t s ea t o feed dur ing development of t h e egg. From t h i s tiine u n t i l a f t e r hatching began, observed numbers remained low. During incubat ion a d u l t s r e l i eved one another a t i n t e r v a l s of about e i g h t days Table 32. Extreme d a t e s of s i g n i f i c a n t events i n t h e breeding cycle of Wedge-tailed Shearwaters, Sand I s l and , Johnston A t o l l , 1963-1969 Year Adults present Egg l ay ing Hatching* Fledging** 1963 ?-1-15 Dec. ? 14-17 Aug.-? ?-1-15 Dec. 1964 11 Mar.-10 Dec. 15 June-? 4-5 Aug.-? 16-30 Nov.-ca. 1 4 Dec. 1965 11 Mar.-ca. 30 Nov 1-15 June-? 1 Aug-16-30 Sept. 1-15 Nov.-10-15 Dec. 1966 12 Mar.-2 Dec. 15 June-? ca. 5 Aug.-3 Sept. l a t e Nov.-15 Dec. 1967 21 Mar.***-? 18 June-? by 18 Aug.-10 Sept . ?-? 1968 20 Mar.-16-31 Dec. 16-30 June-? ca. 10 Aug.-1-15 Sept. e a r l y Nov.-3-16 Dec. 1969 14 Mar.-? 12 June- ca. 1 J u l y 4 Aug.-24 Aug. ?-? *Incubation period about 53 days; of s i x 1969 eggs, 3 hatched between 50 and 54 days, 2 between 52 and 54 days, and 1 i n 53 o r 54 days. **Fledging period about t h r e e months; no exact da t a . ***One b i rd 23 Feb., no o the r s u n t i l 21Mar. (mean = 7.75, range = 4-12, n = 12, POBSP 1963 d a t a ) . Few b i r d s except t hose incubat ing remained through t h e day, but l a r g e numbers returned a t n ight . Most of t h e s e appeared t o be unoccupied birds--ones t h a t d id not l a y o r t h a t l o s t t h e i r eggs. During t h e f i r s t week a f t e r hatching chicks were usua l ly tended by both pa ren t s a t n igh t but by only one dur ing t h e day. Attendance became l e s s r egu la r a s t h e ch ick ' s food demar~ds increased and both parents spent more time feeding a t s e a , but re turned f requent ly , pos- s i b l y every n i g h t , t o feed t h e chick. Maximum numbers appeared i n l a t e August through September. Daytime numbers remained lower than during t h e spr ing cour tsh ip per iod , but a t dusk hundreds streamed i n to t h e i s l a n d , mostly from t h e southwest, and remained through t h e n igh t . Counts of 900 t o 1,000 b i r d s on t h e su r face were made i n August and September 1966. A few hundred more were under ground and not counted. Thus, each n igh t approximately ha l f t h e t o t a l number of b i r d s using t h e i s l and during t h e year re turned during t h i s period. Those wi th chicks more than one o r two weeks old apparent ly fed t h e i r o f f sp r ing e a r l y i n t h e evening and spent t h e reaminder of t h e n igh t ou t s ide the burrows i n l a r g e , loose roos t ing c lubs , probably composed of these and unoccupied b i r d s . Low i n t e n s i t y cour t sh ip accompanied by out- b u r s t s of moaning a s e n t h u s i a s t i c a s those of t h e pre-laying cour tsh ip per iod , continued through the e a r l y f a l l n igh t s . By dawn, most b i r d s had returned t o sea t o feed. Numbers dec l ined i n October, probably because b i r d s without chicks ceased r e tu rn ing . I n November, a d u l t s wi th ch icks began leaving and numbers decl ined sharp ly . The l a s t a d u l t s ceased r e tu rn ing i n e a r l y December. Chicks began leaving t h e i r burrows f o r sho r t periods a t n i g h t by October, and began t o f l edge i n November s h o r t l y a f t e r t h e i r pa ren t s abandoned them. A l l were gone by mid-December. Except f o r one b i rd found 23 February 1967, no Wedge-tailed Shearwaters were known t o have been on Johnston A t o l l between mid-December and mid-March--a period of four months. Presumably t h e b i r d s spent t h i s time a t s ea , feeding and molting. The beginning of t h e pos t -nupt ia l molt has not been observed, but few b i r d s were handled i n l a t e f a l l when i t might have s t a r t e d . Adults have nea r ly completed t h e i r molt by t h e t i m e they r e t u r n i n t h e spr ing . I n f i v e of 12 b i r d s examined 13 Apr i l 1967 t h e d i s t a l primary was only about three- four ths grown on each wing. Body f e a t h e r s of the r e tu rn ing b i r d s have a f r o s t e d appearance which i s soon l o s t by wear. Specimens Specimens of Wedge-tailed Shearwaters from Johnston A t o l l a r e l i s t e d i n Appendix Table 7. Wetmore c o l l e c t e d seven specimens (4 males, 3 females) i n J u l y 1923. POBSP personnel c o l l e c t e d 93 specimens from 1963 through 1969. A l l specimens a r e housed i n t h e National Museum of Natural His tory . This i s a new published specimen. record . Banding and 1nterisl .and Movement POBSp personnel and Amerson banded 6,517 ind iv idua l Wedge-tailed Shearwaters (4,985 a d u l t s and 1,532 young) a t Sand I s l and during 1963- 1969, 1973 (Tables 24 and 33) . Rapid wear and l o s s of aluminum bands made a n a l y s i s d i f f i c u l t because 961 b i r d s had t o be rebanded. Beginning i n 1968 most a d u l t s and a l l chiclcs were banded with Monel meta l bands. Orange, p l a s t i c , leg-streamers were a l s o put on most a d u l t s handled each year but t hese too were l o s t f a i r l y r a p i d l y ; v i r t u a l l y none was found on r e tu rn ing b i r d s a t t h e beginning of each new breeding season. Of t h e 6,517 b i r d s o r i g i n a l l y banded on t h e i s l a n d , 3,635 were recaptured back the re ind ica t ing s t rong t i e s t o t h e i r breeding ground. Six b i r d s , banded a s young i n 1968, were recaptured back on Sand Is land i n November 1973; t h e s e probably had re turned t o t h e i s l and f o r t h e f i r s t time a s they appeared t o be going through pre-breeding cour t sh ip behavior s imi l a r t o t h a t observed i n o ther Proce l la r i formes . The Monel bands on these s i x showed l i t t l e wear. Nine Wedge-tail.ed Shearwaters banded a s a d u l t s a t Johnston A t o l l were recaptured elsewhere: s i x a t French F r i g a t e Shoals and t h r e e a t sea . One banded 1 9 September 1973 was recaptured 8 November 1965 a t sea a t 41'0's and 174'201E, which i s west of Cook S t r a i t , New Zealand. I n a d d i t i o n , e i g h t wedge-tails banded a s a d u l t s elsewhere were captured a t Johnston A t o l l , s i x from French F r i g a t e Shoals and two from Oahu. At-Sea D i s t r i b u t i o n Light phase Wedge-tailed Shearwaters--the phase most prevalent a t Johnston A t o l l and i n t h e Hawaiian Islands--occurred a t s ea i n t h e g r i d southwest of Johnston A t o l l dur ing a l l months but were a t t h e i r h ighes t i n September and lowest during January, February, and March (Table 21 and Fig. 54). Year-to-year v a r i a t i o n s i n dens i ty and rhythm were f a i r l y small. With t h e exception of an anomalously low g r id d e n s i t y i n June, t h e annual populat ion cyc le s on Johnston A t o l l and i n t h e g r id were s i m i l a r from January through J u l y (see Fig. 53). Major d i f f e r e n c e s , however, ex i s t ed between these two a r e a s from August through December. I n t h e g r i d , numbers continued t o inc rease through September, decreased i n October, and increased again through November and December. These were probably post-breeding and non-breeding b i r d s concent ra t ing p r i o r t o , o r during migrat ion. By October most, if not a l l , t hese b i r d s had l e f t t h e a rea . Increased numbers i n t h e g r i d i n November and December probably represent young b i r d s leaving t h e i s l a n d s and perhaps remaining a t sea f o r a month o r more, feeding and ga ther ing s t r e n g t h f o r d i s p e r s a l t o t h e winter ing a rea . Most of t h e b i r d s observed i n t h e g r i d i n December and January were i n apparent f i r s t year plumage. No orange-streamered wedge-tai ls from Johnston were recorded wi th in t h e g r id . A t l e a s t 25 orange-streamered b i r d s were s igh ted , however, i n t h e pe lagic waters around Johnston A t o l l . It i s poss ib l e t h a t a l a r g e p a r t of t h e g r i d populat ion c o n s i s t s of non-breeding b i r d s t h a t belong t o t h e l a r g e r nor th-cent ra l P a c i f i c populat ion of which Johnston b i r d s a r e only one group (POBSP, 1967a; King, 1974). F igure 54. Diurnal occurrence of Wedge-tailed Shearwaters ( l i g h t phase) a t s ea 175 m i l e s southwest of Johnston A t o l l , 1963-1967. T a b l e 33. Banding and r e c a p t u r e s of Wedge-tai led S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1973 A d u l t s Year New band ing R e t u r n s (Rebanded) Recover i e s* T o t a l hand led Young banded T o t a l Banded 1963 1 , 8 1 3 2 0 1 , 8 1 5 153 1 , 9 6 6 1964 939 234 29 1 ,202 309 1 , 2 4 8 1965 53 0 662 (113)** 3 5 1 ,227 38 9 919 1966 1 ,042 1 , 0 4 0 (447) 11 2 ,093 1 5 0 1 , 1 9 2 1967 7 2 196 (64) 4 272 0 72 1968 501 377 (319) 6 884 447 948 1969 88 7 1 (18) 1 1 6 0 0 8 8 "Dead b i r d s . "'"Numbers i n p a r e n t h e s e s a r e numbers rebanded. CHRISTMAS SIIEARWATER Puffinus n a t i v i t a t i s S t a tus Uncommon breeding spec ie s , p re sen t from l a t e January to l a t e September. Nests on Sand I s l and ; previously nested on Johnston I s l and . About 30 b i r d s , ha l f of which at tempt t o breed, re turned each year during POBSP s t u d i e s ; t h r e e t o t e n eggs were l a i d and one t o s i x chicks fledged each year . Adults re turned t o t h e i s l and i n January, l a i d from l a t e March t o e a r l y May, and l e f t t h e i s l and i n ilugust or September. Chicks usua l ly hatched i n May or June and fledged i n August o r September. :?ost success fu l n e s t s were near t h e shore under boards, logs , and concre te s l a b s , or i n an abandoned hunlcer. Attempts t o nes t i n shallow t renches under Lepturus or Boerhavia, i n t h e manner of b i r d s nes t ing on undisturbed i s l a n d s , u sua l ly were unsuccessfu l , probably because the b e s t s i t e s of t h i s type were occupied by t h e l a r g e r and more aggress ive Vedge-tailed Shearwaters. Ecological D i s t r i b u t i o n Johnston I s l and : Wetmore (ms. a ) recorded about 400 Christmas Shearwaters he re i n J u l y 1923 and described t h e colony a s fol lows. There a r e two small co lonies on t h e i s l a n d , where these b i rds congregate amid t h e wedge-tailed shearwaters and have n e s t s i n holes dug t o a shallow depth in. t h e sandy s o i l . During t h e day a l l a r e hidden underground but a t dark they creep out and remain a c t i v e a l l n igh t . Adults a r e c a l l i n g and ca res s ing one another though a l l have l a r g e young molting i n t o f i r s t plumage. These squirm and b i t e when handled and u t t e r a cur ious c a l l COO (given wi th exp i ra t ion of brea th) - 00-00 (made a s brea th is inhated) . The c a l l i s l i k e t h a t of t h e a d u l t P. cuneatus. A t da rk t h e young creep out of t h e i r ho le s and remain i n t h e open but seek s h e l t e r e i t h e r i n heavy g r a s s or underground when t h e sun i s high. Adults show some wear i n plumage. The note of t h e a d u l t s i s a cur ious crowing c a l l coo-coo- oo-00-Koo Koo Kaw, t h e f i r s t p a r t drawn out and t h e l a s t given r a p i d l y . They a r e e s p e c i a l l y voci ferous a t day- break i n t h e morning and f o r an hour a f t e r . Clark (1945b) aga in observed a few i n May 1945. None has been recorded s ince . Sand I s l and : r Wetmore (ms. a ) found about 100 a d u l t s with l a r g e young on Sand I s l and i n J u l y 1923. POBSP personnel recorded t h i s spec ie s here i n small numbers from 1963 t o 1969. Kr id l e r (BSFW, 1973) recorded four n e s t s with eggs i n May 1973. Nesting h a b i t a t i s d iscussed i n d e t a i l i n t h e Populat ion sec t ion . I n summary, they normally n e s t i n shallow t r enches under vege ta t ion , u sua l ly Lepturus, but competition from Wedge-tailed Shearwaters ap- pears t o have d r iven them t o t h e periphery of t h e i s l a n d , where they u s e a v a r i e t y of c a v i t i e s under Logs, boards, concre te s l a b s , and an abandoned bunker (Figs. 55 and 56) . Attempts t o n e s t under vege ta t ion a r e l e s s successfu l because t h e only vegeta t ion a v a i l a b l e t o t h i s spec ies is too spa r se t o provide adequate p ro tec t ion . Figures 43 and 57 show t h e d i s t r i b u t i o n of t h e nes t ing s i t e s used during POBSP s tud ie s . Birds without n e s t s were found i n t h e same gene ra l a r ea a s the n e s t e r s . The e a s t s lope , where most of the unsuccessful n e s t s were loca ted , was a favored roos t ing p lace f o r b i r d s without n e s t s . A few were found a t o t h e r s i t e s s c a t t e r e d over t h e i s l a n d , inc luding the Tournefortia bush nor theas t of t h e t r a n s m i t t e r , t h e unoccupied grass along t h e northwest shore , and t h e southwest i s l e t bunker. Populat ions The mean and ranges of POBSP semimonthly populat ion es t imates during t h e years1964-1969 a r e shown i n F igure 58. Year-to-year v a r i a t i o n s appear t o be more l i k e l y due t o v a r i a t i o n s i n es t imat ing techniques than t o v a r i a t i o n s i n a c t u a l numbers. Nearly a l l Christmas Shearwaters r e tu rn ing t o t h e i s l a n d e a c h year were handled a t l e a s t once. Thus t h e number of new bandings, p lus the number of previous ly banded b i r d s caught , i s a good es t imate of the t o t a l number of b i r d s using t h e i s l a n d each year . This v a r i e d from 18 t o 28 during t h e years 1963-1969 (see Tables 24 and 36). I n a l l yea r s ex- cept 1963, when observat ions by t h e POBSP d i d not begin u n t i l J u l y , and 1966, when incomplete records were obtained, t hese f i g u r e s probably r ep resen t a t l e a s t 90 percent of t h e r e tu rn ing b i r d s f o r t h e r e spec t ive years . Loss of bands may have i n f l a t e d t h e number of new bandings, which would compensate f o r b i r d s missed. The t o t a l number of Christmas Shearwaters r e tu rn ing each year was 25 t o 30. The mean of semimonthly e s t ima tes during t h e period of maximum abundance was about three- four ths t h i s number, which probably i s a good es t imate of t h e number us ing t h e i s l and during each semimonthly period. Wetmore's es t imate of 300 b i r d s on Johnston and 100 on Sand i n mid-July 1923 i s over 20 times t h e number obtained from mid-July v i s u a l e s t ima tes during t h e 1960's. Loss of nes t ing h a b i t a t and crowding by Wedge-tailed Shearwaters appear t o be t h e major causes of the decrease . Both shearwater spec ie s o r i g i n a l l y used s imi l a r habitat--sandy s o i l vegetated with Lepturus. Because both spec ie s are now crowded onto Sand I s l and and wedge-tai ls almost t o t a l l y dominate a v a i l a b l e Leptwus s t ands , t h e smaller Christmas Shearwaters have decl ined t o a much smaller f r a c t i o n of t h e i r o r i g i n a l numbers than have wedge-tai ls . During most i n t e n s i v e m i l i t a r y use of Sand I s l a n d , t h e r e probably were years i n which Christmas Shearwaters were unable t o reproduce a t a11 and t h e populat ion may have dropped even lower than dur ing t h e 1960's. Figure 55. Christmas Shearwater chick, 2 and 112 months old, in shallow trench burrow under L e p t u r u s r e p e n s clump on east shore of Sand Island, Johnston Atoll, 29 August 1966 (POBSP photo by P. C. Shelton). Figure 56. Christmas Shearwater chick, 2 months old, and adults in bunker on east shore, Sand Island, Johnston Atoll, 1 September 1966 (POBSP photo by P. C. Shelton). a Le t u r u s n): &oard z] Concrete S lab East Bunker Figure 57. D i s t r i b u t i o n of Christmas Shearwater n e s t s i t e s , Sand I s l and , Johnston A t o l l , 1963-1969. For tuna te ly , Christmas Shearwaters w i l l n e s t c l o s e r t o water than w i l l wedge-tails. Cav i t i e s under concre te s l a b s , boards, l ogs , and an abandoned bunker, a l l c l o s e t o t h e s h o r e l i n e of Sand I s l and , were t h e s : t e s of most success fu l breeding a t t empt s dur ing t h e 1960's (Table 34) . Cr,mpetition from Wedge-tailed Shearwaters r e s t r i c t e d t h e Christmas Shearwaters t h a t attempted t o n e s t under vege ta t ion t o marginal s i t e s under spa r se cover where n e s t s were exposed t o r a i n , washing sand, and d i r e c t s u n l i g h t , a s a r e s u l t of which these n e s t s were f requent ly abandoned. Nesting success (Table 34) was low f o r a l l years except 1967 and 1968 when s i x and f i v e young f ledged. Low egg production i n 1969 probably r e s u l t e d from t h e weather p a t t e r n d is turbance i n February. Although t h e b i r d s were only beginning cour t sh ip a t t h e time, physio- l o g i c a l changes must have been induced t h a t prevented egg product ion i n seve ra l b i r d s . Nearly a l l l o s s e s were of eggs r a t h e r t han chicks , f o r only two chicks t h a t hatched f a i l e d t o f l edge , both i n 1965. One of t hese was k i l l e d by a dog j u s t before i t would have f ledged; t h e other died much younger but t h e cause of i t s death was not recorded. Egg l o s s e s amounted t o nea r ly ha l f t hose l a i d ; i n a few cases the cause of l o s s was recorded. The two l o s t i n 1964 were inundated by high t i d e s ; two p .e..e..e..e... A d u l t s - Means ..... i s . .. .e Extremes ... / \ ..*.e..*.. ..... Young P .< e. Figure 58. Means and extremes of semimonthly estimates of Christmas Shearwater numbers, Sand Island, Johnston Atoll, 1964-1969. Los t i n 1968 were broken by Wedge-tailed Shearwate r s ; one 1.968 egg was i n f e r t i l e ; and one 1969 egg ~ 7 a s abandoned when sand washed i n t o t h e s h a l l o w n e s t c a v i t y dug under l o o s e Doerhavia . B a r r i n g f u r t h e r d i s t u r b a n c e of Sand I s l a n d , o r f u r t h e r i n c r e a s e i n wedge- ta i l nurnbers, Chr i s tmas Shearwate r s shou ld a t 1ea.st b e a b l e t o ho ld t l ~ e i r own, and migh t b e a b l e t o i n c r e a s e s1 - igh t ly . On t h e north-. tiest c o r n e r of Sand 1sl.and i s a t h i n f r i n g e of d e n s e %eptmus t h a t is n o t c o m p l ~ e t e l y o v e r r u n by w e d g e - t a i l s and t h i s conce ivab ly cou ld be used by Chr i s tmas Shearwate r s . Tab1.e 34. P r o d u c t i v i t y of Chr i s tmas Shearwate r s on Sand Zs:lancl, J o h n s t o n A t o l l , 1963-1969 Number of Chiclcs P e r c e n t P e r c e n t Number of Hatched Pledged of o f Year -Laid - No. % No. Eggs Laid Chicks l iatched 1963 (2)* N a t u r a l Vegetation*** 1 6 6 38 5 3 1 8 l i *Not i n c l u d e d i n t o t a l s . **Under c o n c r e t e s l a b s , l o g s , b o a r d s , o r i n abandoned bunker . ***Lepturus, Boerhavia, o r Tr ibuZus. Annual Cycle From 1963 t o 1969, a f t e r an absence of nea r ly four months, a d u l t s u s u a l l y returned t o t h e i s l and i n l a t e January (Table 35 and Figs . 37 and 58). The f i r s t a r r i v a l s were u s u a l l y seen soaring along t h e e a s t shore a t dusk; by dark they s e t t l e d near t h e nes t s i t e s where they s a t q u i e t l y most of t h e n i g h t , l eaving by dawn. Numbers increased f a i r l y r a p i d l y during February a s more b i r d s re turned each n igh t and court- s h i p began. Maximum numbers occurred i n March when cour t sh ip was most i n t ense . A few were sometimes present during t h e day a t t h i s t ime. Apparent numbers then decl ined s l i g h t l y a s those b i r d s t h a t would produce eggs spent more time feeding a t sea . I n 1969, p a i r s were observed copula t ing on 11 and 15 March. Eggs were l a i d by these b i r d s 3 and 22 A p r i l , r e spec t ive ly . I n both cases one b i r d re turned t o t h e n e s t l e s s than ha l f t h e n igh t s during t h e two weeks before t h e eggs were l a i d . Other n igh t s n e i t h e r re turned . F i r s t eggs were l a i d i n l a t e March every year except 1.969, when they were delayed u n t i l Apr i l . ( In 1966 t h e f i r s t egg was discovered i n Apr i l , but i t had been l a i d sometime before t h a t . ) The de lay i n 1969 probably r e s u l t e d from t h e d i s r u p t i o n of t h e normal weather p a t t e r n i n February; no Christmas Shearwaters appeared from 5 through 9 February, a f t e r a t l e a s t t h r e e had re turned r e g u l a r l y f o r s eve ra l days i n l a t e January and e a r l y February. Laying extended over a period of nea r ly seven weeks, s l i g h t l y longer than f o r Wedge-tailed Shearwaters. I f c l o s e synchrony i n l ay ing depended t o any g rea t ex ten t upon s o c i a l f a c i l i t a t i o n , then i t would he expected t h a t Christmas Shearwaters would he l e s s synchronous than wedge-tails. The small numbers of Christmas Shearwaters nes t ing i n s c a t t e r e d s i t e s around t h e periphery of t h e i s l and would have much l e s s opportuni ty f o r s o c i a l contac t between p a i r s than would be t h e case wi th t h e i r more numerous r e l a t i v e s . Exact d a t e s of egg lay ing and ha tching were obtained f o r only a few eggs; incubat ion averages about 52 days (range 51-54, n = 5) and f l edg ing per iods average about 96 days (range 88-103, n = 6 ) . One a d u l t stayed with t h e ch ick during t h e day f o r t h e f i r s t week o r s o a f t e r hatching, and both pa ren t s u sua l ly returned a t n i g h t f o r t h e f i r s t four t o s i x weeks, a f t e r which only one usua l ly re turned . Chicks began t o venture out of t h e i r n e s t s a t n ight when they a r e two- t h i r d s grown, but they were quick t o seek refuge i f d i s t rubed . Adults abandoned t h e chicks a few days be fo re they f ledged. During t h e period of incubat ion and chick feeding, a d u l t s without eggs or ch icks continued t o r e t u r n t o t h e i s l and a t n igh t . They a r r i v e d a t dusk, soared along t h e e a s t shore u n t i l about dark, then spent t h e n i g h t s i t t i n g i n p a i r s or sometimes i n groups of four or f i v e near t h e beach on t h e e a s t s lope. Those t h a t had l o s t eggs or had nested i n former yea r s usua l ly returned t o t h e s i t e of t h e i r former n e s t o r near t h e nes t ing b i r d s . Low i n t e n s i t y cour t sh ip continued a s long a s these T a b l e 35. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of Chr i s tmas Shearwate r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969 Year A d u l t s P r e s e n t Laying Ha tch ing F l e d g i n g 1963 ? -ea r ly Sep t . 1964 by e a r l y Feb.-ea. 20 Aug. by 29 Mar.-1 Apr. 20-21 May 22-25 Aug. 1965 1 0 Jan.-ca. 1 S e p t . by 29 Mar.-30 Apr. 25 May-22 June 22 Aug. 1966 23 Jan.-30 Sep t . by 2 Apr.-ca. 1 0 May ca. 1 2 June-ca. 1 J u l y 8 Sept.-2 Oct. 1967 28 Jan.-ca. 25 S e p t . ca. 2 1 M a r .-6 May 1 3 May-ca. 29 J u n e ca. 1 3 Aug.-ca. 1 Oct. 1968 by e a r l y Feb.-26 S e p t . ca. 20 Mar. -7 May ca. 5 May-19 June 4 Aug.-27 S e p t . 1969 ca. 24 Jan.-ca. 15 S e p t . 3 Apr.-22 Apr. 24 May-12 J u n e 3 1 Aug.-ca. 20 Sep t . b i r d s were p r e s e n t . A t dawn they a g a i n soa red over t h e e a s t s h o r e , occasiona1.ly c a l l i n g a s t h e y f l e w , b e f o r e head ing o u t t o s e a f o r t h e d a y ' s :Eeeding. These b i r d s ceased relzurning t o t h e i s l a n d abou t t h e t ime t h e f i r s t c h i c k s Eledged. Few bi.rds were examined l a t e i n t h e b r e e d i n g s e a s o n , b u t tigo caught t e n d i n g chiclcs i n ].ate August 1.968 had s t a r t e d t o r e p l a c e t!.le:ir p r i - m a r i e s . Thus t h e mol t a p p a r e n t l y b e g i n s s h o r t l y b e f o r e t h e c h i c k s f l e d g e . B i r d s r e t u r n i n g i n J a n u a r y had compl.ete1.y new pluinage. Specimens Eleven specimens are housed i n t h e USNM (Appendix T a b l e 7 ) . 'This is cons ide red t o b e a new p u b l i s h e d specimen r e c o r d . B a n d i g and I n t e r i s l a n d Movement --- - POBSP personnel. banded 83 Chr i s tmas Shearwate r s on Sand I s l a n d d u r i n g 1963--1969 (Tab les 24 and 3 6 ) . Rapid band v e a r compl ica ted a n a l y s i s of t h e banding d a t a . The al.uminum bands used d u r i n g t h e f i r s t Eive y e a r s of t h e s t u d y se:l.dom l a s t e d more than two y e a r s , s o t h e b i r d s had t o be rcbanded frequent3.y. By 1969 s e v e r a l h i r d s were wear ing t h e i r f o u r t h hands. Beginning i n summer 1968 Monel m e t a l bands were usecl t o reband a d u l t s and t o band a l l . c h i c k s . Recapture.: 9 E 1968 handed b:irds :in 11969 showed L i t t i e o r no wear of t h e Monel m e t a l bands. I l a f o r t u n a t e i y , an ur~