SMITHSONIAN INSTITUTIONUNITED STATES NATIONAL MUSEUMBulletin 113 LIFE HISTORIES OF NORTH AMERICANGULLS AND TERNS ORDER LONGIPENNES BYARTHUR CLEVELAND BENTOJ Taunton, Massachusetts WASHINGTONGOVERNMENT PRINTING OFFICE1921 U. S. NATIONAL MUSEUM BULLETIN 113 PL. I SMITHSONIAN INSTITUTIONUNITED STATES NATIONAL MUSEUMBulletin 113 LIFE HISTORIES OF NORTH AMERICANGULLS AND TERNS ORDER LONGIPENNES BYARTHUR CLEVELAND BENTOf Taunton, Massachusetts WASHINGTONGOVERNMENT PRINTING OFFICE1921 "^ 324643 ^t^f*ni\ ^^^ lsst-c5L?t.'- OH ' ADVERTISEMENT.The scientific publications of the United States National Museumconsist of two series, the Proceedings and the Bulletins.The Proceedings^ the first volume of which was issued in 1878, areintended primarily as a medium for the publication of original, andusually brief, papers based on the collections of the National Museum,presenting newly-acquired facts in zoology, geology, and anthro-pology, including descriptions of new forms of animals, and revisionsof limited groups. One or two volumes are issued annually and dis-tributed to libraries and scientific organizations. A limited numberof copies of each paper, in pamphlet form, is distributed to specialistsand others interested in the different subjects as soon as printed.The date of publication is recorded in the tables of contents of thevolumes.The Bulletins., the first of which was issued in 1875, consist of aseries of separate publications comprising chiefly monographs oflarge zoological groups and other general systematic treatises (oc-casionally in several volumes), faunal works, reports of expeditions,and catalogues of type-specimens, special collections, etc. The ma-jority of the volumes are octavos, but a quarto size has been adoptedin a few instances in which large plates were regarded as indis-pensable.Since 1902 a series of octavo volumes containing papers relating tothe botanical collections of the Museum, and Imown as the Gontrihu-tioris from the National Herharium., has been published as bulletins.The present work forms No. 113 of the Bulletin series.WlLIilAM DeC. RaVENEL,Administrative Assistant to the Secretary.,In charge of the United States National Museum.Washington, D. C. INTRODUCTION. This Bulletin contains a continuation of the work on the life his-tories of North American birds, begun in Bulletin 107. The samegeneral plan has been followed and the same sources of informationhave been utilized. Nearly all of those who contributed materialfor, or helped in preparing, the former volume have rendered similarservice in this case. In addition to those whose contributions havebeen previously acknowledged, my thanks are due to the followingcontributors : Ph(>tographs have been contributed, or their use authorized, byD. Appleton & Co., S. C. Arthur, A. M. Bailey, R. H. Beck, B. S.Bowdish, L. W. Brownell, G. G. CantM'ell, F. M. Chapman, H. H.Cleaves, Colorado Museum of Natural History, E. H. Forbush, A.O. Gross, O. J. Heinemann, A. L. V. Manniche, W. M. Pierce, M. S.Ray, J. Richardson, R. B. Rockwell, R. W. Shufeldt, J. F. Street,University of Minnesota, C. H. Wells, J. Wilkinson, and F. M. Wood-ruff.Notes and data have been contributed by S. C. Arthur, R. H. Beck,F. H. Carpenter, H. H. Cleaves, E. H. Forbush, F. C. Hennessey, R.Hoffmann, F. C. Lincoln, H. Massey, O. J. Murie, C. J. Pennock,J. H. Rice, Katie M. Roads, and G. H. Stuart. With the consent ofDr. L. C. Sanford and R. H. Beck, the American Museum of NaturalHistory has placed at the author's disposal Mr. Beck's extensive notesmade on the Brewster and Sanford expedition to South America.The distributional part of this Bulletin has been done mainly bythe author, with considerable volunteer help from Mr. F. SeymourHersey, whose time is now otherwise occupied. Dr. Louis B. Bishophas devoted much time to revising the paragraphs on distributionand on plumages.Our attention has been called to an error in Bulletin 107. On page32 a quotation from Dr. T. S. Roberts was inserted as referring tothe food of the eared grebe; this really refers to the food ofFranklin's gull and not to that of the grebe.Readers of Bulletin 107 have suggested some changes. Conse-quently, in this and subsequent Bulletins in this series, the exactdetails will be given, when available, in such casual records as aregiven; but it must be remembered that no attempt will be made to VI BULLETIN 113, UNITED STATES NATIONAL MUSEUM.mention all casual records ; only a few can be given, to suggest thelimits of the wanderings of the species. Another addition of value,suggested and furnished by Dr. T. S. Palmer, is information regard-ing reservations and the species which are protected in them. Assome readers have questioned the scale on which the eggs are illus-trated, it seems desirable to say that in Bulletin 107, in this one, andin subsequent Bulletins, all eggs are, and will be, shown exactly life-size, the plates being produced by an exact photographic process.The Author. TABLE OF CONTENTS. Page.Family Stercoraridae 1Catharacta skua 1Skua 1HabitH 1Distribution 6Catharacta cliilensis 7Chilean Skua 7Habits 7Distribution 7Stercorarius iwmarinus 7Pomarine jaeger 7Habits 7Distribution 13Stercorarius parasiticus 14Parasitic Jaeger 14Habits 14Distribution 19Stercorarius longicaudus 21Long-tailed jaeger 21Habits 21Distribution 28Family Laridae 29Pagophila alba 29Ivory gull 29Habits 29Distribution 35Rissa tridactyla tridactyla 36Kittiwake 36Habits 36Distribution 43Rissa tridactyla pollicaris 44Pacific kittiwake 44Habits 44Distribution 48Rissa brevirostris 49Red-legged kittiwake 49Habits 49Distribution 51Larus byperboreus 52Glaucous gull 52Habits 52Distribution 60Larus leucopterus 62Iceland gull 62Habits 62Distribution 64 Yin TABLE OF CONTENTS.Family Laridae?Continued. Page.Larus glaucescens 65Glaucous-winged gull 65Habits 65Distribution 73Larus kumlieni 73Knmlien's Gull 73Habits ^ 73Distribution 75Larus nelsoni 76Nelson's Gull? 76Habits- 76Distribution 76Larus marinus 77Great black-backed gull 77Habits __- 77Distribution : 85Lainis scbistisagus 86Slaty-backed gull 86Habits 86Distribution 89Larus occidentalis 89Western gull 89Habits 89Distribution 98Larus fuscus affinis 99British lesser black-backed gull 99Habits 99Distribution 101Larus argentatus 102Herring gull i 102Habits 102Distribution "SSSJ~-SZ^-S--. 119Larus thayeri .__1_1______ 120Thayer's gull 120Habits 120Distribution 122Larus vegae . 122Vega gull - 122Habits - 122Distribution 124Larus californicus 124California gull 124Habits 124Distribution 131Larus delawarensis 132Ring-billed gull 132Habits 132Distribution 139Larus brachyrhynchus 140Short-billed gull 140Habits 140Distribution 145Larus canus 146 TABLE OF CONTENTS. IX'Family Laridae?Continued. PageMew gull 14GHabits 146Distribution ^ 147Larus heennanni 148Heermann's giill 148Habits 148Distribution 153Larus artricilla 1,54Laughing gull 154Habits :__ 154Distribution 162Larus franklini 163Franklin's gull 163Habits _^_^___::^ii__ 163Distribution '_'_'_I'll'__ll__ 174Larus Philadelphia 175Bonaparte's gull 175Habits 175Distribution 179Larus minutus 180Little gull 180Habits 180Distribution 182Rhodostethia rosea 183Ross's gull 183Habits 183Distribution 190Xema sabini 191Sabine's gull 191Habits 191Distribution 196Gelochelidon nilotica 197Gull-billed tern 197Habits 197Distribution 202Sterna caspia . 202Caspian tern 202Habits 202Distribution 210Sterna maxina 211Royal tern 211Habits 211Distribution 218Sterna elegans 219Elegant tern 219Habits 219Distribution 220Sterns sandvicensis acuflavida 221Cabot's tern 221Habits 221Distribution 226Sterna trudeaui 227 X TABLE OF CONTENTS.Family Laridae?Continued. ^^s^-Trudeau's tern 227Habits 227Distribution 228Sterna forsteri 229Forster's tern 229Habits 229Distribution 235Sterna hirundo 236Common tern 236Habits 236Distribution 248Sterna paradisaea 249Arctic tern 249Habits 249Distribution 255Sterna dougalli 256Roseate tern 256Habits 256Distribution 264Sterna aleutica 265Aleutian tern 265Habits 265Distribution 269Sterna antillarum 270Least tern 270Habits 270Distribution 278Sterna fuscata 279Sooty tern 279Habits 279Distribution 286Sterna anaetheta 287Bridled tern 287Habits - 287Distribution 289Chlidonias nigra surinamensi.s 290Blaclj tern 290Habits 290Distribution 298Chlidonias leucoptera 299White-winged black tern 299Habits 299Distribution 301Anous stolidus 301Noddy 301Habits 301Distribution 309Family Rynchopidae 310Ryncliops nigra 310Black skimmer 310Habits 310Distribution 318References to bibliography 319Explanation of plates 329Index 339 LIFE HISTORIES OF NORTH AMERICAN GULLSAND TERNS, ORDER LONGIPENNES.By Abthur Cleveland Bent,of Taunton., Massachusetts. Family STERCORARIDAE, Skuas and Jaegers.CATHARACTA SKUA Briinnick .SKITA.HABITS.The following quotation from the graphic pen of Mr. F. St. Mars(1912) gives a better introduction to this bold and daring speciesthan anything I could write, and his article, The Eagle Guard, fromwhich I shall quote again, is well worth reading as a strilring char-acter study : Then the scimitar wings shut with a crisp swish, and he became a statue indull, unpolished bronze, impassively regarding the polecat, who lay with herback broken, feebly struggling to drag into cover. It is a shock to the humannerves to see the life blasted out of a beast almost 'twixt breath and breath ; what one moment is a gliding, muscular form, instinct with life and energy,confident in power, and the next moment a crumpled heap of fur, twitchingspasmodically. But it was a searchlight on the reputation of the eagle guardand the stories one had heard anent tlie superstitions of the natives.The polecat, being hungry with the gnawing hunger of a mother and pre-suming on a swirl of mist, had tried to steal up the knoll to the two great eggsthat lay in the hollow atop all unguarded. Had come then a thin, high, wliirringshriek, exactly like the noise made by a sword cutting through the air, and asingle thud that might have been the thud of a rifle bullet striking an animal.Then?well, then the scene described above.Big, powerfully built, brown with the black brown of his own native peatbogs, armed to the teeth, long and slash-winged, whose flight feathers were liketlie cutting edge of a sword, insolent with the fine, swelling insolence of power,and greatly daring, no wonder men had chosen him as the eagle guard, thismighty bird, tliis great skua of the naturalists, this Bonxie, mascot, and super-stitious godling of the fishermen. Wall ! he was a bird.We know so little about the skua, as an American bird, that Ishall have to draw largely from European writers for its life history.It is rare on the American side of the Atlantic Ocean, and is notknown to breed here regularly, although it probably does so occasion-ally or sparingly in Greenland or on the Arctic Islands. 1 2 BULXjETIN 113, UNITED STATES NATIONAL MUSEUM.Nesting.?Yarrell (1871) says:The great skua arrives in tlie Shetlands about the end of April, and its nest,which consists of a neatly rounded cavity in the moss and heather of thehighest moorlands, is prepared in the latter half of May. According to Maj.Feilden, the birds appear to prepare several nests before they decide on usingone. There is no difficulty in finding the nests, as the parent birds at onceattack any intruder upon their domain v^ith fiex'ce and repeated swoops. Whenhandling the nestling the editor found their assaults were unremitting; firstone bird and then the other wheeling short, and coming down at full speed,almost skimming the ground. At about 15 yards' distance the strong clawedfeet are lowered and held stiffly out, producing for the 'moment a very ungainlyappearance, and it seems as if the bird would strike the observer full in thecenter of the body, but on quickly raising the hand or stick the bird rises also,the whirr and vibration of its pinions being distinctly heard and felt. Itsordinary flight is soaring and stately. On leaving the territory of one pair,the attack is taken up by another, and so on ; for the great skuas do not nestin close proximity.Morris (1903) writes:The nest of the skua is of large size, as well as somewhat carefully con-structed ; tlie nsaterials used being grasses, lichens, moss, and heath. The birdplaces it on the tops of the mountains or cliffs in the neighborhood of the sea,but not on the rocks themselves. They build separately in pairs.Eggs.?The skua lays ordinarily two eggs, rarely three, and some-times only one. These vary in shape from ovate or slightly elongatedovate to short ovate. The shell is smooth, with a dull luster. Theground color is " Saccardo's olive," " Isabella color," or " deep olivebuff." The markings are usually not profuse and consist of spotsand blotches, scattered irregularly over the egg, of " sepia," " bis-ter," " snuff brown," or '' tawny olive." There are also usually a fewfaint spots or blotches of pale shades of drab or gray. Rev. F. C. E..Jourdain has collected for me the measurements of 68 eggs, whichaverage 70.58 by 49.43 millimeters; the eggs showing the four ex-tremes measure 76.3 by 50.4, 71.5 by 53.3, and 62 by 44.5 millimeters.Young.?Macgillivray (1852) quotes Captain Vetch as saying:The young bird is a nimble, gallant little animal, and almost as soon ashatched leaves the nest. On the approach of danger he secretes himself inholes or behind stones with great art, and when captured at least makes a showof defense that is quite amusing.Plumages.?I have never seen the downy young, but Coues (1903)describes it as " buffy-gray, ruddier above than below." Ridgway(1887) quotes Dresser as calling it " brownish or cinnamon-gray,rather darker in color on the upper parts than on the under surface ofthe body."I have not been able to examine enough specimens to come to anydefinite conclusions as to the sequence of molts and plumages. Coues(1903) gives the following good description of the young of the year:Size much less ; bill weaker and slenderer ; cere illy developed ; striae notapparent and its ridges and angles all want sharpness of definition. Wings U. S. NATIONAL MUSEUM BULLETIN 113 PL. 2 LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 3 short and rounded, the quills having very different proportional length fromthose of adults; second longest, third but little shorter, first about equal tofourth. The inner or longest secondaries reach, when the wing is folded, towithin an inch or so of tip of longest primary. Central rectrices a little shorterthan the next. Colors generally as in adult, but duller and more blended,having few or no white spots; reddish spots dull, numerous, and large, espe-cially along edge of forearm and on least and lesser coverts. On underpartsthe colors lighter, duller, and more blended than above ; prevailing tint lightdull rufous, most marked on abdomen, but there and elsewhere more or lessobscured v\-ith ashy or plumbeous. Remiges and rectrices dull brownish-black;their shafts yellowish-white, darker terminally. At bases of primaries thereexists the ordinary large white space, but it is more restricted than in adults,and so much hidden by the bastard quills that it is hardly apparent on outsideof wing, though conspicuous underneath.Young birds may become indistinguishable from adults at the firstpostnuptial molt, when a little over a year old, but perhaps not fora year or two later.Adults seem to have but one complete molt?the postnuptial?inAugust. Adults can be distinguished by their larger size and by theelongated feathers of the neck with the whitish central streaks.Food.?Yarrell (1871) writes of the food of the skua:Their food is fish, but they devour also the smaller water birds and theireggs, the flesh of whales, as well as other carrion, and are observed to tear theirprey to pieces while holding it under their crooked talons. They rarely taketlie trouble to fish for themselves, but, watching the smaller gulls and ternswhile thus employed, they no sooner observe one to have been successful thanthey immediately give chase, pursuing it with fury ; and having obliged itfrom fright to disgorge the recently swallowed fish, they descend to catch it,being frequently so rapid and certain in their movements and aim as to seizetheir prize before it reaches the water. The stomachs of a pair which wereshot were full of the flesh of the kittiwake, and the castings consisted of thebones and feathers of that small gull. Heysham has noticed an adult femaleon the coast of Cumberland, which allowed herself to be seized while she wasin the act of killing a herring g-uU. It also feeds on fish offal, and the editorfound by the side of a nestling some disgorged but otherwise uninjuredherrings of large size.Behavior.?In appearance as well as in habits the skua seems toshare the attributes of the Raptores and the Laridae; its strong,hooked bill and its sharp, curved claws enable it to stand upon andrend asunder the victims of its rapacious habits. Its flight is alsosomewhat hawk like. Yet it stands horizontally and runs aboutnimbly like a gull. Morris (1903) says that it "soars at times at agreat height, and flies both strongly and rapidly, in an impetuous,dashing manner." Mr. Walter H. Rich has sent me the followingnotes on the flight of this species : When on the wing, which is the greater part of the time, the skua showsin the air hawk like, rather than like the gulls, with whom we rather expect 4 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. to find its resemblances. Its appearance in tlie air is somewhat lil^e thebiiteoniue hawks, except that its wing action, in its seemingly restrained powerand forceful stroke, suggests the unhurried flight of a falcon, or, perhaps,more accurately?since the wings are at all times fully opened, employingtheir full sweep in their action, their primaries slightly separated at the tipsand slightly recurved?the majestic flight of an eagle. The wing spread isample, the wing well balanced in its proportions of length and breadth, wellcombined to produce both power and speed. The figure is somewhat burlyand chunky as compared with the lighter appearance of the gull and themore racy lines of the yager. The impression of muscularity is heightenedby the short, square-cut tiiil, carried somewhat uptilted, giving the fowl anappearance unmistakable in the eyes of one having once recognized it. Thispeculiarity of tail, which to me seemed slightly forked instead of havingthe central feathers lengthened, as in others of this group, together with thebroad white patch across the bases of the primaries, furnishes a good fieldmark for the identification of the species.Macgillivray (1852) says:Its voice resembles that of a young gull, being sharp and shrill, and it is fromthe resemblance of its cry to that of the word skua or skui that it obtains itspopular name.Mr. Rich's notes state : Whatever the case elsewhere, or the fishing grounds this seemed a silentspecies. The writer heard no sound at all which he was able with certainty totrace to it during his acquaintance vdth it.The most interesting phase of the skua's life history is its behaviortoward other species. It is certainly a bold and dashing tyrant,more than a match for anything of its size and a terror to many birdsand beasts of larger size. Mr. F. St. Mars (1912) describes itsattack on the golden eagle, which dared to venture too near its nest,in the following graphic words : Some minutes elapsed, in spite of the warnings, before the human eye couldhave made out a faint dot growing out of the mist round the tail of an inlet.It enlarged rapidly, however, that dot, and one saw that it was really a real,live eagle, a golden eagle of Scotland. Mind you, there was none of that sublimesoaring in the infinite that the books tell of. He came, as any mere commonbird might have come, beating up along the shore with heavy, flapping flight,which, by the way, looked much slower than it really was, and he said nothingas he came.The picture, as it stood, of that somber, bronze-gold winged giant, beatingslowly up against the wind in a setting of dim gray sky, jade sea, and dark-velvet land, was very fine. It seemed that nothing could have added to itsbold, wild grandeur. Then .something seemed to move across the heavens veryquickly, and there was a hissing sound as if a mighty sword had cleaved the air.Followed then a second phenomenon just like the first, and almost in thesame instant one realized two distinct facts: Firstly, that the two skuas wereno longer near their nest ; and, secondly, that the eagle had, with five stu-pendous flaps of those vast wings, shot upward into the clouds. LIFE HISTORIES OF NORTH AMERICAN GUULS AND TERNS. 5At the same instant it seemed as though a big brown projectile hurtled pastexactly beneath him, and a fraction of a second later, as though another onehad hit him. There was a burst of feathers and a whirl. The eagle appearedsuddenly to grow much larger, miraculously to sprout an extra and smaller,thinner pair of wings, and to reel in his flight, recover, reel again, turn halfover, as if grappling some invisible foe, drop like a thunderbolt some 200feet, and then break into two pieces, the larger piece slanting upward on theone hand and the smaller executing the same wonderful aerial evolution on theother.Then were the facts made plain. The smallei' portion was the skua. He haddarted like lightning upon the eagle's back and clung there for a second or two ? only for a second or two, but it seen?ed minutes while the two fell?after theking had avoided his mate's first reckless, headlong, crazy rush.I have no hope to describe to you what followed, because the laboring humaneye was far too slow to see and the brain to grasp the electric-quick passage ofevents. I only know that one was dimly aware that some stupendous battlewas going on up there in the dim northern heavens ; that bodies, large bodies,bursting with life and a dozen uncurbed wild passions, were sweeping andswerving, and swooping, and swaying, and streaking, and stabbing, and slash-ing, and striving, and screaming in one wild welter of wildering speed. And allthe while the land below, save for the liuddled sheep, lay as deserted as if ahand had come down and swept it clean of life. Yet one knew that in realityhundreds and hundreds of sharp eyes were watching from cover that battle ofthe overlords of the air and calculating the chances of life upon its issue.Slowly, second by furious second, inch by hard-fought inch it looked from theearth, but mile by mile it was really, up there in the unbounded airy spaces,the battle receded, receded upward and northward, till the straining eye wasat last only conscious of a faraway blur, a dancing of specks, as it were gnats,on the vision, and then, with an almost audible sigh from the hidden specta-tors, of nothing.Mr. Rich's impressions of the behavior of the skua are expressedin his notes as follows : This is the overlord of the fishing grounds, fearing no bird here. "Whetherthe skua would successfully contest with the black-backed gull the writer isunable to state, as the two did not come together under his observation, buthe thinks that the skua need have little uneasiness as to the outcome of bat-tle. The difference in size between the black back and the skua is mostly amatter of measurements, due in part, at least, to the skua's shortness ofrudder. In bulk and weight there is less difference, probably, than is shoAvnby these figures, and in physical powers, judging from appearances, there islittle to choose between them. Of the two, the skua's armament seems thebetter fitted for damaging an enemy, and he seems to possess greater speed andskill in maneuvering?a flight of greater power and control than has hisrival, who, gull-like, is a drifter rather than a flier. Certain it is that thehag, tern, kittiwake, and herring gull move respectfully aside when the " seahen " comes sailing above them, for all these he harries and robs constantly,performing in the realms of the sea the same robber tactics which the raptorialbirds carry on among the feathered people ashore. Are the hags or the gullssquabbling over a bit of waste or striving to tear a " poke-blown " fish whichhas drifted away from the steamer's side ; over the struggling mass there comesthe shadow of broad wings ; a heavy body drops among them regardless ofwhat may be beneath it ; the weaker move respectfully aside and leave the 6 BULLETIN 113, UNITED STATES NATIONAL MUSEUM.newcomer in undisturbed possession of tlie spoil. Over his shoulder the skuagazes at the steamer, making only now and then a tentative pull at the bodyof his prey, until it has floated to a safe distance, when he begins to rip andtear it with his powerful beak. To lose all interest in that particular morsel,hag or gull that comes near the spoil needs to look but once at that loweredhead with its bristling crest, and the powerful wing upraised to strike.Whiter.?The status of the skua as an American bird is basedlargely on its occurrence on the fishing banks off the coasts of New-foundland and New England. Probably the birds which occurthere in winter are of this species, but the following notes by Mr.Rich suggest the possibility that the birds seen there in summer maybe of one of the Antarctic species : In the main, the " sea hen " seems to have been considered a winter visitorto our coasts, somewhat unusual during the summer months, yet my recordsshow its presence here from June 19 to November 5, with its period of greatestabundance from August 12 to September 10 (this in the "South part of thechannel," 3-5 miles east; south from Sankaty Head, 68? ?42' W. ; 41? ?20' N.),with numbers diminishing thereafter until the last appearance therein notedon November 5, 1913. The writer remained upon the fishing grounds 21 dayslater, but did not again note its presence there.These facts have suggested to Mr. Norton that the " sea hen " of the sum-mer months may have come from the Antarctic with the shearwaters, returningthither to breed among the penguin rookeries of that little-known continent onthe underside of the world; while the skuas of the winter months may comefrom the northern breeding grounds of the species.It is regrettable that I was unable to collect any spc^cimens with which tomake comparisons and to go deeper into this matter. There would have beenvery little difliculty in getting material, as the " sea hen," while more carefulthan the " gull-chasers," was not very shy, and shots at 30 yards or even lesswould have been frequent. DISTRIBUTION.Breeding range.?Islands of the North Atlantic Ocean, Greenland,Iceland, the Faroe and Shetland Islands, Said by Kumlien to breedat Lady Franklin Island north of Hudson Strait.Winter range.?The North Atlantic Ocean, occasionally reachingland. From the Great Banks, off Newfoundland, and Georges Bank,off Massachusetts, to New York (Long Island) . In Europe from theBritish Isles and Norway south to Gibraltar. Occasional in theMediterranean Sea and on inland waters.Spring migration.?Migration dates in North America are so fewas to appear little more than straggling records. Labrador: Straitsof Belle Isle, June 22.FaM migration.?Birds reach Georges Bank in July. Massachu-setts dates : Ipswich, September 17 ; Woods Hole, August 30 and Sep-tember 19; Pollock Rip, September 10; and Nantucket Shoals, Octo-ber 17. Recorded from New York (Long Island) as early asAugust 10. LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 7Casual records.?Accidental inland in New York (Niagara River,spring, 1886).Egg dates.?Iceland: Twenty-four records May 20 to June 23;twelve records June 3 to 15. Greenland : One record June 21.CATHARACTA CHILENSIS (Bonaparte).CHILEAN SKUA.HABITS.The preceding species, Catharactu skua., has been reported, as astraggler, on the coasts of California and Washington, where speci-mens have been taken, as recorded below.These records have always seemed open to question as it seemedunlikely that a bird of the Atlantic Ocean would stray so far awayfrom its normal habitat.There are at least two other species of skua, which are fairly com-mon in certain parts of the South Pacific and South Indian Oceans,which would be much more likely to wander to the coast of Cali-fornia. Thinking that these records might refer to CatharactacMlensis or Catharacta lotmhergi, I opened correspondence regard-ing them with Mr. Harry S. Swarth, which resulted in his sendingme one of the birds. After consultation with Mr. Robert CushmanMurphy, who is familiar with these species in life, and after compar-ing it with series of specimens of chilensis, lomihergi, and antarcticain various museums in Cambridge, New York, and Washington, Ihave decided to provisionally refer these birds to the above species,Catharacta chileiisis, of which they probably represent an immatureplumage or a dark phase. DISTRIBUTION.Breeding range.?Unknown.Range.?Most abundant on the coasts of Chile and Peru, but foundon both coasts of southern South America, from Rio Janeiro, on theAtlantic side, to Callao, Peru, on the Pacific side. Wanders north-ward, perhaps regularly, in the Pacific Ocean to Japan (SagamiSea, August 23, 1903), California (Monterey Bay, August 7, 1907,and August 4 and September 21, 1910), Washington (off Gray's Har-bor, June 28, 1917), and British Columbia (off Vancouver Island,June 20, 1917). STERCORARIUS POMARINUS (Temminck).FOMABINE JAEGER.HABITS.To most of us this and the other jaegers are known only as sum-mer and fall visitors on our coasts or on the fishing banks, wherethey are constantly harassing the smaller gulls, the terns, and theshearwaters, from whom they obtain by force a large part of theirfood supply. The pomarine is the largest of the three, but by no174785?21 2 8 BULLETIN 113, UNITED STATES NATIONAL MUSEUM.means the most aggressive. Few of us have ever seen it on its breed-ing grounds, which lie within the Arctic Circle, where it is widelyscattered over the boundless plains of the marshy tundra.Spring.?Dr. E, W. Nelson (1887) says of its arrival in northernAlaska : The earliest arrival of this bird in spring was May 13 at the Yukon mouthwhere the writer found it searching for food along the ice-covered river chan-nels. They became more common, until, by the last of the month, from a dozento 20 might be seen every day,Mr. Frank C. Hennessey, who accompanied the A. P. Low expedi-tion to the regions north of Hudson Bay, says, in his notes, that " thefirst of this variety was seen to arrive in the spring at Winter Har-bour on May 29th."Nesting.?Very little has been published on the nesting habits ofthe pomarine jaeger. Mr. Hennessey, in the notes referred to above,which he kindly sent me, states that these birds are " abundant aboutWinter Harbour, where they breed on the low, flat, marshy land inthe neighborhood, choosing the small mounds or slight elevations thatabound in these places upon which to rear their brood. The nest isa slight depression in the soil of the elevation and just deep enoughto admit the eggs and breast of the bird. No material is used in itsconstruction, but the bottom is covered with much loose soil and rub-bish apparently blown in accidentally." Mr. C. Boyce Hill (1900)published the following account of the nesting habits of this speciesin Siberia : On our way down the Yenisei the steamer which was towing us fortunatelyran ashore on one of the numerous sand banks which abound in this river. Isay fortunately because it enabled us to discover this skua nesting. Afterhaving inquired the probable duration of our stoppage, Popan and I agreed toexplore the small islands near at hand?a grovip named the Brekotsky. Wetook one each, and on mine, a large, flat marsh, I observed a Pomatorhine skua,which was presently joined by another. The birds did not appear at all demon-strative nor to resent intrusion, like the long-tailed skuas, so I thought theycould not be nesting. But after much searching and watching I observed onesettle right in the center of the marsh, so at once proceeded to the spot. Thebird rose when I was within a few yards of it, and to my delight I saw thenest with two eggs. I waited a few moments for the skua to come within shotand killed it ; after pursuing its mate, I captured that also. The nest was amere depression in the ground, on a spot rather drier than the surroundingmarsh, and to reach it I was at times up to my knees in swamp; so that hadit not been for a foundation of ice at a depth of from 18 inches to 2 feet fromth? surface I do not think I should have been able to record this event. Ialso found nesting on this island some scaup ducks and red-necked phalaropes.Mr. Ludwig Kumlien (1879) found this species breeding on theGreenland coast under very different conditions. He writes : I have, however, nowhere found them so very common as on the southernshores of Disko Island ; at Laxbught and Fortuna Bay there must have been LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 9many hundred pairs nesting. Their breeding place was an inaccessible cliffabout half a mile from the seasliore. The greater number of the birds nestinghere were in the plumage described in Doctor Coues's monograph of the Laridaeas the nearly adult plumage; but there were also a good many birds that wereunicolored blackish brown all over, but with the long vertically twisted tailfeathers. That these were breeding I think there can be no doubt, as I sawthem carrying food up to the ledges on the cliff, for the young I suppose.Eggs.?The Pomarine jaeger lays two or three eggs to a set,usually the former. They are said to be scarcely distinguishablefrom certain eggs of the parasitic jaeger or of the mew gull, butare more pointed. The shape is ovate or pointed ovate. The shellis smooth and slightly glossy. The ground color varies from " brown-ish olive " or " Brussels brown ' to " olive lake " or " dark olive buff."They are rather sparingly spotted with "bone brown," "bister," " chestnut brown," or " snuff brown," and occasionally with under-lying spots or blotches of various shades of drab or gray. The meas-urements of 49 eggs, in various collections, average 62 by 44 milli-meters: the eggs showing the four extremes measure 72.6 by 44.9,68 by 48, 57.2 by 43.6, and 58.5 by 40 millimeters.Plumages.?The young when first hatched is covered with longsoft down, of plain colors and unspotted ; the upper parts are " clovebrown " or " olive brown " and the under parts " drab " or " lightdrab." The plumage appears first on the scapulars, back, and wings,then on the breast, and the full juvenal plumage, which is not dis-tinctly separated from the first winter, is acquired before the youngbird is fully grown. The first winter plumage is the well-knownbrownish mottled plumage, in which the body feathers and particu-larly the scapulars are heavil}^ barred transversely with dark brownsor dusky tints and tipped with rufous or pinkish buff; the centraltail feathers are only slightly elongated beyond the other rectrices.This plumage is worn with slight changes all through the first year,or until the first postnuptial molt, which begins in June and lastsuntil October. The rufous or buff edgings gradually fade out towhite during the winter; during the molt into the second-yearplumage August birds show old barred feathers with white edgingsand new barred feathers with rufous edgings. The second winterplumage is still mottled or barred, but is much lighter colored;the browns are grayer and there is more white, the rufous edgingssoon disappearing. There is less barring on the under parts andthe belly is often wholly white centrally; the under tail-coverts areheavily barred with white and dusky. There are sometimes signs ofthe golden collar in this plumage. If there is any molt in thespring, it is only partial, and probably the young bird does notbreed in this plumage the second spring.At the second postnuptial molt the following summer, when thebird is about 2 years old, the third-year plumage is assumed. This 10 BULLETIN 113, UNITED STATES NATIONAL MUSEUM.plumage is practically the same as the adult in many individuals;the upper parts are uniformly dark, except that the white and goldencollar encircles the neck; the two central tail feathers become muchelongated ; the under parts are mainly white, with more or less duskymottling on the neck, upper breast, and sides; and the lower abdo-men and under tail-coverts become dusky, but in some individualsthese are veiled or mixed, more or less, with wliite. There is greatindividual variation in the amount and extent of the dusky mottlingin the white areas, in the amount of v/hite in the dark under tail-coverts, and in the extent of the white and golden collar at this age ; but as there is not much further progress to be made toward ma-turity, the third-year birds may be considered practically adult. Thefully adult plumage, without much mottling in either the light orthe dark areas and with the fully developed golden collar, increasesin perfection with subsequent molts; the clear dark crissum andunder tail-coverts are assumed when the bird is about 3 years old,though vigorous birds may acquire them before that time. I havenever seen a specimen in which the neck, breast, and shoulders wereentirely free from dusky mottling.Birds in the dark phase of plumage, apparently, undergo the samesequence of plumages to maturity, though I have not been able totrace the changes so satisfactorily. In the first-year plumage theyare much darker than in the light phase, with the white barring muchmore restricted. During the second year they are almost whollydark with some whitish and rufous edgings above and below. Thethird-year and adult plumages are hardly distinguishable, both beinguniformly dark, but some specimens show an indication of the goldencollar, more or less distinctly, which are probably the older birds.The molt of the contour feathers in both phases occurs in summer,from June to October, and the flight feathers are molted in October,beginning with the inner primaries and the central rectrices. Theprenuptial molts of both young birds and adults are probably in-complete, but specimens of winter and early spring birds are tooscarce to demonstrate it.Food.?The predatory feeding habits of the jaegers are familiarto everyone who has studied the habits of our sea birds during thelatter part of summer and fall. They are the notorious pirates andfreebooters among sea birds, the highwaymen that persecute theirneighbors on the fishing grounds and make them "stand and de-liver." It is no uncommon sight on the New England coast to seeone or two of these dusky robbers darting through a flock of hover-ing terns or small gulls, or giving chase to the lucky one that hascaught a fish, following every twist and turn in its hurrying flight LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 11 as it tries to dodge or escape, close at its heels as if attached by aninvisible string. At last, in desperation, the harassed tern dropsits fish and the relentless pursuer seizes it before it strikes the water.Occasionally the indignant tern voids its excrement instead, v?hichthe jaeger immediately seizes, as if it were a dainty morsel.Off Chatham, Massachusetts, we often saw this and the next spe-cies, which are called " jiddie-hawks" by the fishermen, minglingwith the shearwaters and browbeating them as they do the gullsand terns. As soon as the shearwaters began to gather about ourboat to pick up the pieces of cod liver that we threw overboard,the jaegers would appear and take a hand in the general scramblefor food. They are quick to sense the idea that a gathering flockof sea birds means a feast to be obtained by force. The " haglets "are greedy feeders, and soon gulp down what pieces of food theycan find, but they have learned by many a painful squabble thatthey are no match for the active, fighting "jiddie-hawks," and theyare soon forced to disgorge or to surrender the field.Mr. Kumlien (1879) says that on the Greenland coast "they liveto a great extent upon the labors of the kittiwake, though they donot hesitate to attack Larus leucopterus^ and even glaucus. They aredestructive to young birds and eggs. It is a common sight to seefive or six after one gull, which is soon made to disgorge, and thenthe jaegers fight among themselves for the morsel, which often getslost in the melee." In addition to the food stolen from other birds,the pomarine jaeger lives on what it can pick up in the way of offal,carrion, and scraps thrown from the galley. It devours young birdsand eggs, and even small mammals, such as mice and lemmings.Mr. Albert W. Tuttle (1911) publishes the following account, con-tained in a letter from Mr. Allen Moses, of Grand Manan, NewBrunswick : I saw a pomarine jaeger catch a pjialaiope. There was a pair of the jaegers.The female started after tlie phalaropes and chased them a long time. Theywere too smart for her, and after a long chase she separated out one, and thenthe male gave chase, and in a few minutes, with the two chasing the little fel-jow, one caught him within a hundred yards of the vessel ; then they both lightedin the water and ate him.Behavior.?Were it not endowed with splendid powers of flightthe pomarine jaeger could never perform the feats indicated above.It is not only swift and poweiful, but it has wonderful commandof its powers on the wing. It can be easily recognized by its superiorsize and by the peculiar shape of its elongated, central tail feathers,which are broad and blunt and are held with their vanes in a verti-cal plane, like a rudder. Its ordinary flight is steady and direct,with rather slow, constant wing beats. Mr. Walter H. Kich haa 12 BULLETIN" 113, UNITED STATES NATIONAL MUSEUM. contributed the following notes on one of its spectacular perform-ances :On several occasions I have seen the " gull chaser " turn a complete backsomersault in the air to make a dive upon some piece of food on the water whichthe sweeping gale had caused it to overrun. Often, too, it thus makes itspiratical raids upon some luckless hag, which, almost too late, it finds inpossession of a morsel which it deems too dainty to be wasted on a meresquealing shearwater. And ?o it rises against the breeze, turns itself upsidedown and. with wings half closed, darts at its victim from above like a lance.But the hag stands to his guns ; a squealing, choking remonstrance, a mightygulp, and if the jaeger has luclc he may capture a small fragment of the spoil.Mr. Rich says that the usual " call is a sharp ' which-yew,' alsoa squealfy whistle, and occasionally a squealing note like the ' week-week ' of the herring gull." Doctor Nelson (1887) ssljs that it " has alow, harsh, chattering cry when feeding with its companions."Its behavior toward other species, which has been partially shownabove, is not above criticism; its motto seems to be that might makesright; it therefore uses some discretion in the choice of victims forpersecution. The terns and the kittiwakes are the ones most regu-larly abused, the ring-billed and the herring gulls are less frequentlypersecuted, and it seldom ventures to attack the glaucous or thegreat black-backed gulls. Size and strength do not always bringcourage, and the pomarine jaeger seems to be lacking in the latterquality. Doctor Nelson (1887) writes:They are clumsy and cowardly as compared with their smaller relatives.When one of this species chances to cross the path of the smaller species, thelatter almost invariably gives chase and beats its clumsy antagonist off thefield by repeatedly darting down from above. This attack embarrasses thelarge bird, so that it flinches and dives and often alights and watches anopportunity to escape from its nimble assailant. One that was driven toalight in the river thrust its head under water at every swoop of its assailantand exhibited the most ludicrous terror. When on the wing they usually wardoff an attack from one side by a half-closed wing, and if above, both wings areraised, forming an arched shield above the back.Fall.?^The fall migration of the jaegers is governed largely bythe food supply, which depends on the movements of the fish onwhich the gulls, terns, and shearAvaters feed. On the New Englandcoast we usually look for the jaegers in August, especially where thebluefish or mackerel are running in schools and driving the smallfry to the surface. During seasons when these fish are scarce thejaegers and shearwaters are absent, perhaps following other schoolsof fish far out at sea. And when the bluefish and mackerel move offthe coast in the fall the jaegers disappear with them. They areseldom seen on our coasts in winter. We do not know very muchabout their winter range and habits, but they probably spend thisseason roaming at large over the open ocean wherever they can finda chance to ply their trade as pelagic pirates. LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 13DISTRIBUTION.Breeding range.?Northern parts of the Northern Hemisphere.In North America east to central Greenland (latitude 64? to 73? N.).South to Cumberland (Exeter Sound) and Hall Peninsula (GrinnellBay), Melville Peninsula (Winter Harbor), and the Arctic coast ofNorth America. West to northwestern Alaska (Kotzebue Sound toPoint Barrow. North to Melvnlle Island, Banks Island, NorthSomerset, and probably others of the Arctic islands. In Europefrom Iceland to Spitzbergen, and Nova Zembla, perhaps occasionallyon the coast of northern Norway; also in northeastern Siberia andprobably the entire Siberian coast. Siberian birds have been de-scribed as a distinct subspecies, but it is doubtful if on good grounds.Win ter range.?Poorly defined. Probably in Southern Hemispheresouth to Peru (Callao Bay), northern Australia (Cape York),Burma, and South Africa (AValfisch Bay) ; also said to occur oninland waters of Europe south to the Mediterranean, and in smallnumbers from the coast of southern California to the Galapagos;occasional in winter in the Orkney Islands, off the south coast ofEngland, and off Japan. It seems probable that these more northernrecords are not true wintering birds, but late migrants or stragglers.Spring migration.?Northward off both coasts of North America.Early dates of arrival: North Carolina, Cape Hatteras, April 18;Massachusetts, May 23; Maine, May 29; New Brunswick, GrandManan, May 26 ; Melville Peninsula, Winter Harbor, May 29 ; Green-land, June 10; California, San Francisco Bay, May 5; Alaska, St.Michael, May 23, and Point Barrow, May 23 to June 6 ; northeasternSiberia, Liakoff Islands, June 20.Fall migration.?Southward by same routes. Early dates ofarrival : Newfoundland, Bonne Bay, August 16 ; Nova Scotia, SableIsland, September 3; Rhode Island, September 13; New Jersey,October; Alaska, Kodiak Island, August 15; Washington, PugetSound, September 7; California, Monterey Bay, August 2; Mexicancoast, October 5; Peru, Callao Bay, November 17. Late dates ofdeparture: Northeastern Greenland, latitude 75? 49' N., August 6;western Greenland, Disco Island, September 6; Nova Scotia, Halifax,October 4; Maine, late October; Massachusetts, December 9; RhodeIsland, October 11 ; New York, Long Island, October 30 ; New Jersey,December; Alaska, Point Barrow, August 15 to September 20; Wash-ington, Puget Sound, October 22; California, Monterey Baj^, Octo-ber 27.Casual records.?Spring records from Nebraska and Michigan andfall records from Pennsylvania, Ohio, Illinois, and Missouri areprobably casual stragglers, but they may indicate a limited migra-tion through the interior from Hudson Bay. 14 BULLETIN 113, UNITED STATES NATIONAL MUSEUM.Egg dates.?Point Barrow, Alaska: Twenty-four records June 12to 27 ; twelve records June 17 to 20. Iceland : Three records May 21,June 1 and 28. STERCORARIUS PARASITICUS (Linnaeus).PABASITIC JAEGEH.HABITS.Contributed by Charles Wendell Toimisend.As one watches a flock of terns whirling like driven snow, nowhere, now there, and ever and anon plunging for fish, one may some-times see a dark, hawk-like bird suddenly appear on the scene andspread devastation in the ranks. With relentless energy he singlesout and pursues some hapless individual until it drops its prey. Thisis a jaeger, a gull-like bird, with hawk-like characteristics, A moreappropriate name for him would be robber rather than jaeger orhunter, for he obtains his food by robbing other birds. He has,however, all the grace and agility of the true hunting birds?thehawks?but his actions rarely end in bloodshed. After all robberyis a less serious crime than murder, but the term robber is oppro-brious, while that of hunter is not, so it is perhaps well that the nameremains as it is.The parasitic jaeger is circumpolar in its distribution and breedsthroughout the barren arctic grounds in North America, Greenland,Europe, and Asia. In Europe it nests as far sonth as the Shetlands.It winters from the southern part of its summer range along thecoast even as far as Brazil, Australia, and the Cape of Good Hope,but in the interior of the continents it is only of casual occurence.Spring.?In the brief arctic spring, when the ice is breaking up andthe snowdrifts are dwindling, the parasitic jaeger arrives on thebreeding grounds on the tundra near the shores of the Arctic Ocean,or at a distance from the sea on the shores of ponds or lakes. Itgenerally nests apart, not in communities. Of its courtship nothingis known. It is possible that the " wailing cries " described by Nelsonand mentioned later may be in the nature of the love song. Whensurprised near the nest, Nelson (1887) says, "it creeps along theground with flapping wings to decoy away the intruder."Nesting.?The nest is a mere depression in the soil. Macfarlane(1908) says it is "scantily lined with a few withered leaves andgrasses." Grinnell (1900) in the region of Kotzebue Sound, Alaska,says " the nest was a slight saucer-shaped depression on a low mossyhummock on the tundra. This depression was scatteringly linedwith bits of white lichen, such as grow immediately around thenest." Thayer and Bangs (1914) report that Koren found it in U. S. NATIONAL MUSEUM BULLETIN 113 PL. 3 Kolyma Delia , Siberia. J. Koren. Point Barrow, Alaska. Parasitic Jaeger.For DEscRrPTioN see page 329. T. L. Kiehardson. LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 15northern Siberia nesting *' in dry spots in swamps." Eussell (1898)at the mouth of the Mackenzie, says that "the nest was simply alevel bit of dry moss on the tundra a few yards from the water'sedge.''Eggs.?Only two eggs are laid and one brood hatched. Nelson(1887) says the eggs are laid in northern Alaska by June 5. Theegg is ovate in shape, of a dull olive varying to green, gray or brownground color, with spots, blotches, and lines of a sepia, drab, darkchocolate, and umber-vinaceous color. These markings are some-times distributed with great uniformity over the whole egg or gath-ered as a wreath about the larger end. The measurements of 50eggs in various collections average 57 by 41 millimeters; the eggsshowing the four extrenies measure 61 by 41, 58 by 43, 51 by 40.5,and 56 by 38 millimeters.Plumages.? [Author's note: I have never seen a small specimenof the downy young of the parasitic jaeger, but a half-grown youngin my collection, which is still more than half downy, has the downof the upper parts uniform "? natal brown," paler on the head andneck, and shading off to " drab-gray " on the under parts. There isno indication of any mottling anywhere. The juvenal plumage iswell advanced on the wings and scapulars, where it evidently appearsfirst; the feathers are appearing through the down all over thebreast and belly and on the upper part of the back ; the tail feathersare bursting their sheaths.The sequence of plumages to maturity is practically the same, inboth phases, as in the pomarine jaeger, except that the parasiticjaeger normally acquires its fully adult plumage when a little over2 years old. The first-year plumage is heavily barred above andbelow with rufous edgings, which fade and wear away during thefall and winter. The second-year plumage is less heavily barred,with narrower and whitish edgings above, with much more white inthe underparts, with heavily barred under tail-coverts, with some-what elongated central rectrices and sometimes with a suggestion ofthe golden color. At the second postnuptial molt, when the birdis from 25 to 27 months old, the fully adult plumage is assumedwith no mottling or barring anywhere, with the dusky under tail-coverts and crissum and with the elongated central rectrices.During this m.olt the upper body plumage is completed first, andthe last signs of immaturity to disappear are the barred feathers ofthe chest and flanks. The postnuptial molt of both adults andyoung is complete and occurs in August, September, and October,the wings being molted in October. There is probably an incom-plete prenuptial molt also, but material is lacking to show it satis-factorily. Fall adults in fresh plumage have the chin, throat, and 16 BULLETIN- 113, UNITED STATES NATIONAL MUSEUM.neck clouded with light drab and the dark crown less pronouncedthan in spring. This disappears partially by wear, but I have seenone adult, taken in California on April 29, in which this plumagewas being replaced by a partial molt.Adult parasitic jaegers can be distinguished in life at a long dis-tance by the downward extension of the drab mantle on the sides ofthe neck which seems to form a partial collar ; this is entirely absentin the long-tailed jaeger; the long central tail feathers are morepointed and are held differently in flight from those of the pomarinejaeger, as explained under that species; these feathers are, however,an unsafe guide by which to distinguish the parasitic and long-tailedjaegers, as there is much individual variation and overlapping.These last two species can hardly be distinguished in life in the im-mature plumages. For the best characters by which they can bedistinguished in the hand I would refer the reader to Dr. LeonhardStejneger's (1885) excellent remarks on the subject.In the dark phase, which may prove to be a distinct species, thesequence of molts and plumages is practically the same as outlinedabove, though the birds are much darker in all stages. During thefirst year the brown edgings are conspicuous, but during the secondthey are replaced by narrower and whiter edgings, the under tail-coverts being heavily barred in both cases. The adult plumage iswholly sooty, with sometimes a trace of the golden collar.]The proportions of the two phases vary considerably. At Ips-wich in the migrations, which extend over most of the summer, thebirds in light phase outnumber the dark birds in the proportion of8 or 10 to 1. On the Labrador coast I found those in the dark phasemore numerous in proportion than at Ipswich. Richardson (1825)says that on the banks of the Coppermine River in the beginning ofJuly the greater part of them had dark abdomens. Grinnell (1900)in Alaska found a sooty bird mated with a light one and remarksthat " one could scarcely believe them to be of the same species." Hesays that half of this species in June and July were in the darkplumage. Thayer and Bangs (1914) mention two pairs in northernSiberia, where all four birds were in the light phase, and one pairat Kodiak Island, Alaska, where the birds were in the dark phase.Nelson (1887) mentioned a similar dark couple. The difference be-tween the two phases seems as great as that between the greater andthe sooty shearwaters.Food.?The feeding habits of the parasitic jaeger vary consider-ably with the locality. The host on which it preys is in some places,as on the New England coast, the common tern, although the arctic,roseate, and least terns, as well as the Bonaparte's gull, maj^ in placesbe added. On the eastern Labrador coast I found the ffreat flocks of LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 17kittiwakes to be the chief source of its supplies, as also is the case inBaffin's Land, for Kumlien (1879) says:This species seems to depend on liissa tiidactyla for the greater part of itsfood.Anderson (1913), under the heading "Parasitic jaeger," says:The jaegers are the terror of the smaller birds, spending their time cease-lessly hawking back and forth over the tundra looking for eggs and youngbirds. Large numbers of eggs of eiders and gulls are destroyed in the rookeriesby tlie jaegers. Whenever the Arctic terns are nesting their neighbors are com-paratively safe, as the belligerent little terns speedily cause any maraudingjaeger to beat a hasty retreat. I have also seen ruddy turnstones drive ajaeger away from the nests. I once observed a pair of jaegers chasing a flockof sandpipers. One sandpiper flew out of the flock, the jaegers in pursuit.They seemed to work together, one darting in while the other turned. Thesandpiper finally escaped by flying upward until almost out of sight, and thejaegers finally gave up the chase. * * * gome other birds will also attackthe jaegers, which are really cowardly birds when heartily opposed. I have ontwo or three occasions seen a rock ptarmigan fly fiercely at a jaeger whichcame too near lais nesting place and put the jaeger to ignominious flight.Its calling makes it one of the most interesting sea birds towatch. The advent of a jaeger among a flock of terns occasionsloud cries of anger among the latter as they scatter to the rightand left, while the hunter, singling out one individual, chases itwith great energy. No matter how skillfully and rapidly the vic-tim twists and turns, now up, now down, now to one side, nowthe other, sooner or later, with a few exceptions, it acknowledges de-feat by dropping the fish from its beak or by disgorging the con-tents of its gullet. These, the jaeger, with great skill and agility,catches in mid-air and swallows at once, or on other occasions car-ries hanging from the beak for a short distance before satisfyingits appetite. Sometimes it alights on the water, the better to enjoyits meal. Nelson (1887) says:They are very greedy, and frequently swallow so much that they are unableto fly until a portion is disgorged.The victimized tern meanwhile vents its wrath at the robbery inno uncertain language and must again set to work for its living.But the jaegers are not always successful. Thus, on one occasion,I saw a parasitic jaeger pursue a common tern in a straight line fornearly a mile, eventually to give up the chase. Not infrequentlytwo hunters combine on one victim. Thus I have notes of twojaegers at Ipswich, one in the dark, the other in the light phase,that relentlessly followed a common tern. Tlie bird that securedthe prize was at once pursued by his companion and accessory intheft. On another occasion two jaegers at Ipswich were chasinga tern that twisted in sharp angles and small circles over the beach 18 BULLETIN 113, UNITED STATES NATIONAL MUSEUM.Finally the tern dropped the fish, which one of the jaegers securedin mid-air. Later the two dashed into a flock of about a hundredterns and chased them right and left. The terns screamed anddarted around in great confusion; some retaliated by chasing thejaegers.Although this bird well justifies its name parasitic^ it occasionallydoes some foraging for itself; thus King (1836) says that it also "subsists on putrid fish and other animal substances thrown up bythe sea." Turner (1886), at St. Michael, Alaska, says it eats "fishesthat had been cast on the beach, shell fish, and other animal food.They also eat the berries of Empetrum nigrum.'''' The latter is thecrow berry or the curlew berry of the north, the berry on which thecurlew formerly fatted in countless numbers. Turner also relatesan instance where a parasitic jaeger picked up a freshly torn-offmuskrat skin that was floating on the surface of the water.It seized the skin in its beak and then passed it to its claws, by which it car-ried it off a little distance and began to strip the adhering muscle and fatfrom it.Nelson (1887) reported that this species eats also shrews, mice, andlemmings. Eifrig (1905) found bones and feathers in the stomachs.Seton (1908) says that in the region of the lakes of the barrengrounds " it lives much like a hawk or a raven, coming when a cari-bou is killed to share in the oflal. Once saw one capture a Laplandlongspur on the wing, and have often seen it pursuing ground squir-rels." Preble (1908) gives the stomach contents of two taken near theGreat Slave Lake; the first contained various insects and the bonesof a small bird, evidently a young tern, and the other a dragon fly,various beetles, and a small fish. Anthonj^ (1906) says:These deep-sea individuals had their stomachs tilled to overflowing with fishspawn about the size of No. 5 shot, evidently of some species spawning on thesurface where the bird could pick it up without trouble. I have seen this jaegerin Bering Straits diving for surf smelt, together Avith Pacific kittiwakes; but,like all of their group, they found it difficult to get below the surface, even withthe help of a drop of 6 or 8 feet above the water, and seldom neglected an op-portunity to rob the Arctic tern or kittiwake.Behavior.?The flight, swimming, and diving of this species haveall been mentioned in the feeding habits. While the first is rapid,graceful, and falcon-like, the two last are seldom indulged in, and notvery efficient. It is, indeed, a bird of the air and outside of thebreeding grounds is rarely seen on shore. On one occasion, however,at Ipswich, I saw a flock of 10 of these birds on the smooth, hardbeach.In the chase of terns, it is the tern that uses its vocal powers, andthe voice of the jaeger is rarely heard. Nelson (1887) says: LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 19On cloudy days or in the dusky twiliglit, these birds have a habit of utteringloud wailing cries, interspersed with harsh shrieks, which are among the mostpeculiar notes heard in the northern breeding grounds.Mr. W. Elmer Ekblaw says of the habits of this jaeger in Green-land:The jaeger not only steals the food away from the other birds, but also preysupon their eggs and young. In 1914 I found in one day's tramp two eider nestsand one nest of the ring-necked plover that had been despoiled by this ravager.The pierced egg shells were scattered about the nests, as if the jaeger had de-lighted in the destruction he had wrought. The knots and sandpipers of the landbirds and the kittiwakes and terns of the sea birds cordially hate the jaeger. Inprotection of their nests and young these birds often valiantly attack and driveoff the greedy jaeger, but usually he pursues them vindictively until they yieldto him. He is the particular enemy of the kittiwakes, and whenever he dashesinto a flock of them his vicious screams scatter them panic stricken. He thensingles out one for his victim and pursues him relentlessly with buteoninetenacity of purpose.Disliked, as parasitic jaegers must be by their victims, they arewell able to take care of themselves and have few destructive enemies.Even man, although eagerly taking the eggs for food on the breed-ing grounds, disdains to eat the robber bird. It may, like thestrongest of sea birds, at times succumb to the tempest. King (1836)records that one in a storm '* sought refuge from the raging elementsunder the lee of our tent."Fall.?The fall migration of the young of the year begins inAlaska, according to Xelson (1887), after the 20th of September andthe birds keep out to sea on the New England coast. I have seenadults at Ipswich as early as July. Here they pursue their callingamong the terns until these birds leave for the south, whither theyfollow them by September, and continue the same methods of mak-ing a living during the winter.DISTRIBUTION.Breeding range.?Arctic and subarctic regions of both hemispheres.In North America east to Greenland (Disco Bay and Baffins Bay andprobably north to Thank God Harbor. Soutii to northern Labrador(Killinek), and northern Hudson Bay (Southampton Island), cen-tral Keewatin (near York Factory), southern Mackenzie (GreatSlave Lake), southwestern Alaska (Alaska Peninsula and KodiakIsland), and the Aleutian Islands. West to Bering Sea coast ofAlaska. North to the Arctic coast of Alaska and Mackenzie, alsoBanks Land (Mercy Bay), Melville Island (Winter Harbor), andother Arctic Islands to about 80? north latitude. Has been recordedin summer in southeastern Alaska (Glacier Bay) and may occa- 20 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. sionally breed. In the Old World breeds from Iceland, the FaroeIslands, northern British Isles (north coast Scotland, Orkney, andShetland Islands, and many of the Hebrides), along the Arctic coastand islands of Europe and Asia to northeastern Siberia. South to theCommander Islands and probably the Kurile Islands.Breeding grounds protected in the following national reservationin Alaska: Aleutian Islands (as Agattu, Amchitka, and Kiska).Winter range.?From Florida (Gulf coast) and southern Cali-fornia (Point Concepcion) southward along both coasts of SouthAmerica to Argentina (Mar del Plata) and Chile (Valparaiso) andoccasionally as far as the Straits of Magellan. In the Eastern Hemi-sphere along the western coast of Europe and Africa to the Cape ofGood Hope; also southwestern Asia from the Persian Gulf to theMekran and Sind coasts, and occasionally New Zealand andAustralia.Spring migration.?Northward along both coasts. Early dates ofarrival: Off Jacksonville, Florida, April 9; New Jersey, Stone Har-bor, May 27 ; Massachusetts, May 24 and 31 ; Greenland, Thank GodHarbor, June 14; Washington, Tacoma, May 17; Alaska, St. Michael,May 7; Point Barrow, May 29; Banks Land, May 31; MackenzieRiver, June 8. Late dates of departure : Straits of Magellan, March6; Chile, Valparaiso, March 28; Florida, Matanzas Inlet, May 18;Pennsylvania, Renova, June 18; Ontario, Toronto, June 20; south-ern Labrador, June 21.Fall migration.?Southward along both coasts and irregularly inthe interior. Early dates of arrival : Nova Scotia, Sable Island, Sep-tember 9; New Hampshire, Seabrook, September 2; Massachusetts,August 30; Rhode Island, September 2; New York, Long Island,August 6; Brazil, October 26; Argentina, Mar del Plata, October9; southern Alaska, Cook Inlet, August 22; Washington, PugetSound, September 2; Chile, Valparaiso, November 6. Late dates ofdeparture: Ontario, October 20; Massachusetts, October 22; RhodeIsland, November 27 ; South Carolina, Charleston, November ; Well-ington Channel, September 2; Alaska, Point Barrow, September 9,and St. Michael, September 16 ; Pribilof Islands, October 18 ; AVash-ington, Puget Sound, November 8; California, Monterey Bay, De-cember 12.Casual records.?Fall records from the interior are so nmnerousthat they indicate a regular migration route in limited numbers.Egg dates.?Iceland: Sixteen records. May 21 to June 24; eightrecords. May 26 to June 14. Northern Canada: Twelve records,June 10 to July 8 ; six records, June 29 to July 8. Northern Alaska : Four records, June 19 and 20 and July 10 and 18. Shetland Islandsfive records, May 16 to June 26 ; three records, May 30 to June 15. U. S. NATIONAL MUSEUM BULLETIN 113 PL. 4 St. Michael, Alaska F. S. Hersey. -t*''^ > ,St. Michael , Alaska. Long-Tailed Jaeger.For description see page 329 LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 21STERCORARIUS LONGICAUDUS VieiHot.LONG-TAILED JAEGER.HABITS.On the rolling Arctic plains or tundra back of Nome, Alaska, wefound these handsome birds very common and a conspicuous featurein the landscape, where they had probably reared their young andwere spending the summer in congenial surroundings. Some of themwere almost constantly in sight, and it was a pleasure to watch theirgraceful evolutions on the wing, as they coursed about the grassyborders of the little tundra ponds in search of food or perched onthe little mossy hummocks to rest or to watch for passing birds thatthey might rob, or for some small mammal on which they mightpounce. Certain of these little mounds seemed to be favorite lookoutpoints for certain individuals or pairs, as there were signs of con-tinued occupancy, and we frequently saw the same mound occupiedat various times; perhaps each pair of birds has a sort of feudaldomain of its own, from which intruders are driven away.SpHng.?The long-tailed jaeger retires to its Arctic summer homevery early in the season and arrives on its breeding grounds in ad-vance of its congeners. Dr. E. W. Nelson (1887) says that it arrivesin the vicinity of St. Michael about May 12 or 15, but is not numer-ous until 10 days or more later. Mr. Lucien M, Turner (1886)writes : On their first arrival they are somewhat gregarious, though this may be dueto the limited portions of ground free from snow. At this time the little poolsof the low ground are being rapidly thawed out ; many cracks in the heaWngf9ea ice expose the water to view. These places are then scanned for food.When the ice in the lakes and larger ponds is melted, these birds usually arehovering in the vicinity, or seated on some knoll watching a gull or tern divefor a fish.Nesting.?Doctor Nelson (1887) says of the nesting habits of thisspecies near St. Michael:The mating occurs with a gi'eat amount of noisy demonstration on the partof several rivals, but once paired the birds keep by themselves, and early inJune deposit their eggs in a depression on the mossy top of some knoll uponrising gi'ound. In one instance, on June 16, while I was securing the eggs of aMacrorhamphus, a pair of these jaegers kept circling about, uttering harshscreams and darting down within a few feet. As I appreached the spot wherethe snipe's eggs lay I had noticed these birds on a knoll just beyond, but hadpaid no attention; but as the birds kept leaving me to hover over the knolland then return to the attack, I examined the spot, and there, in a cup-shapeddepression in the moss, lay two dark greenish eggs marked with an abundanceof spots. During the breeding season these birds and the prece