PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM
issued
SMITHSONIAN INSTITUTIONU. S. NATIONAL MUSEUM
Vol. 108 Washington : 1958 No, 3404ADVANCES IN OUR KNOWLEDGE OF THE HONEY-GUIDES
By Herbert Friedmann
In the following pages I have brought together new information onvarious aspects of the biology of the honey-guides that has come toattention since the publication of my book in 1955. Together withthese additional data, I have made such comments as seem necessary,either for their proper evaluation or for their allocation with respectto earlier knowledge. Only two phases of honey-guide studies are notincluded: Purely systematic data, and my continuing investigationson wax digestion, the results of which will be presented separately.In addition to such notes as have appeared in print and which arehere collated, I am indebted to the following for unpublished obser-vations: J. P. Chapin, W. R. Ingram, C. H. Jerome, D. W. Lamm,H. M. Miles, B. Neuby-Varty, R. H. Stevenson, V. G. L. van Someren,and J. M. Winterbottom.Additional Data on Eggs and Egg-LayingBecause of the difficulties attached to study of ovulation in para-sitic birds, one must always be alert for incidental data bearing on thistopic. The new information is as follows:1. Greater honey-guide, Indicator indicatorOne observation bearing on the time of day of ovulation comes tome from J. M. Winterbottom. On Sept. 16, 1943, in the northwestern46936fr-68 309
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corner of the Livingstone District, Northern Rhodesia, he caught afemale greater honey-guide on the nest of a hoopoe in a hole in an anthill. The bird had already laid its egg. He watched it go to thenest, and walked up at once, so it was only a matter of seconds, halfa minute at the most, that the bird was on the nest. In answer tomy query, Winterbottom informs me that this took place during thehot part of the day, between 11 a. m. and 2 p. m.A female collected April 28 at Enugu, eastern Nigeria, by Serle(1957, p. 415) had two large yolked ova in the ovary and two rupturedegg follicles, indicating that at least four eggs would have been laid.It may be recalled that earlier data of the same type (Friedmann,1955, p. 136) suggested, in one case at least, that eight eggs wouldhave been laid by one bird. We still do not know what the usualnumber may be.Recently, H. A. Roberts (1956, p. 114) has stated that, when aboutto lay in a barbet's nest, the hen honey-guide goes there accompaniedby the male, and that the latter acts as a lure to draw away the poten-tial hosts from their nest, thereby giving the hen the chance to enterit and deposit an egg. Roberts writes that the female barbet rushesout of the nest hole as the honey-guides approach, and back into itagain as they depart a short distance, this performance "being re-peated until she becomes rather exhausted. At this stage the femalehoney-guide conceals herself nearby, and as soon as both barbetspursue the increasingly bold male honey-guide, the female honey-guide makes a dash for the hole. Usually a short lull among the con-testants now follows which enables the female honey-guide to deposither egg. Should the barbets try and return too soon, the male honey-guide at once takes action to lure them away . . . ." This accountis comparable to one by Millar which I have previously described(Friedmann 1955, pp. 136-137), and as I wrote then, it is "difficult tobelieve that the male accompanies the female to the nests of the po-tential hosts, as there are no data suggesting anything comparable tomating in these parasites. That the male should act as a foil, todraw off the barbets on guard while the female deposits her egg, seemslike too good a story not to have entered into the recording of what-ever may have actually transpired." In the case described above byWinterbottom, no male honey-guide was noted. However, we stillhave so few du*ect observations of the act of egg deposition that it isadvisable to keep an open mind on this matter, even though it seemsrather unlikely that the males attend the laying females.2. Sharp-billed honey-guide, Prodotiscus regulusSerle (1957, pp. 416-417) collected a female at Enugu, eastern Ni-geria, on September 27 that had an egg in membrane in the oviduct
HONEY-GUIDES?FRIEDMANN 311and three large yolked ova and two ruptured follicles in the ovary,indicating that at least five eggs could have been laid.Additional Host RecordsOur knowledge of the life histories of all the honey-guides is still soimperfect that it is to be expected that additions to the lists of knownvictims will be made for a long time to come. Besides these new hostspecies, further data on previously poorly documented ones have alsocome to attention in the past three years. The total supplementarydata, presented here under the various species of honey-guides, donot change the present picture materially but merely add to the totalrecorded information and help to orient more properly some of theearlier information.1. Scaly-throated honey-guide. Indicator variegatusOne additional host has been recorded for this still infrequentlyobserved honey-guide. The case is of sufficient interest to quote theoriginal account in some detail.Jackson's tinker-bird, Pogoniulus bilineatus jacksoni (Sharp)Van Someren (1956, p. 220) writes that
... at another nest I knew to hold young, I noted fresh chippings on theground and thought perhaps another hole was being started, but there was nosuch cavity. Sitting down in cover, I heard dull tapping coining from the nesthole, then noticed chippings coming out .... With a sharp knife, I cut acircular opening . . . and exposed the nest. The chamber and tunnel had beenconsiderably enlarged and within was a three-quarters grown variegated honey-guide. It was remarkable that the hen honey-guide had been able to force herway in and lay her egg in the original small chamber, and moreover, how did thebarbets come to appreciate that the chamber was too small to accommodate thechick! Yet, here they were, enlarging the chamber to ensure the comfort of theirfoster child! I replaced the circle of wood and sealed it in. The young honey-guide was seen in the forest two weeks later, attended by the foster parents . . .It is fortunate that, in this case, the young parasite was featheredsufficiently to make its identification certain. In my book (1955, p.105) I listed one record for the Uganda race of this tinker-bird,Pogoniulus bilineatus nyansae (Neumann), and echoed Jackson's(1938, p. 734) doubts that either Indicator variegatus or /. indicatorcould possibly get inside the small nest opening to lay there, or thatthe young parasite, when ready to leave, could get out through it. Itnow appears that our doubts were needless. Van Someren (1956,p. 221) writes that he has seen a "variegated honey-guide strugglinginto a hole scarcely large enough for her to enter."2. Greater honey-guide. Indicator indicatorThe new data on this, the best known of the honey-guides, whoserecorded hosts now number 32 species, or, including subspecies, 38forms, are as follows:
312 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io8Striped kingfisher, Halcyon chelicuti chelicuti (Stanley)Previously known from a single instance near Marandellas, SouthernRhodesia, this kingfisher is listed as a host by Smithers, Irwin, andPaterson (1957, p. 89), possibly on the basis of the same record.Neuby-Varty, the discoverer of the first case, has recently written meof what may be a second case. Early in December 1955, near Maran-dellas, he watched a striped kingfisher at a nest hole about 20 feet upin a tree. Suddenly, a freshly dead kingfisher nestling, about 4 or 5days old, fell out of the opening and to the ground. He picked it upand noted tiny punctm-es anterior to the wings that looked very muchlike the bill hook wounds of a nestling honey-guide. Unfortunately,he was not able to get to the nest and so could not prove that therewas a honey-guide chick present. It may be recalled that in the caseof nestling ejection by the young honey-guide in a nest of the crestedbarbet (Friedmann, 1955, pp. 147-148) the young barbets were ejectedalive and unharmed, possibly because the nest stump had been brokenoff and there was little depth left to the nest cavity, thereby makingejection easier. In the present instance, it may be that the depth wasgreater and the parasite did not attempt eviction until after it hadimmobilized its nest mate.Cinnamon-breasted bee-eater, Melittophagus lafresnayii oreobates (Sharpe)In his recent book, van Someren (1956, p. 190) writes that he hastaken eggs of the greater honey-guide from nests of this species inKenya Colony, but does not give any indication of how many suchcases he found. In addition, W. R. Ingram informs me (in litt.)that he once found a nest of this bee-eater, also in Kenya Colony,containing one egg of Indicator indicator as well as some pecked eggsof the host. This bee-eater was not known to be parasitized priorto these observations.Crested barbet, Trachyphonus vaillantii vaillantii RanzaniTo the two records given in my book (1955, pp. 147-148) may beadded two more, both of parasitized nests found in Southern Rhodesiaby C. T. Fisher, and mentioned to me by Mr. H. M. Miles (in litt.)Banded sand martin, Riparia cincta cincta (Boddaert)One record for this hitherto unrecorded host, but the identificationof the species of honey-guide involved is only inferential. CaptainR. H. Stevenson informs me that a honey-guide's egg was found ina nest of this swallow in the Selukwe Reserve, Southern Rhodesia,about the end of November or the first days of December 1955. It ispossible that either Indicator indicator or /. minor might be involved.In the absence of details, such as notes on the status of the two inthat locality, dimensions of the egg, etc., it is not possible to allocatethe record. It would seem more likely to be /. indicator becausethat species makes use of nests in holes in the ground nauch more
HONEY-GUIDES?FRIEDMANN 313frequently than does /. minor, but both are kno\\'Ti to do so. Intheir recent book on the birds of Southern Rhodesia, Smithers, Irwin,and Paterson (1957, p. 89) list this swallow as a host of the greaterhoney-guide. I do not know if this is based on Captain Stevenson'srecord or if it is still another case.Kenya anteater-chat, Myrmecocichla aethiops cryptoleuca (Sharpe)Previously only two records were known to me, to which two moremay now be added, indicating more definitely something of theregularity, if not frequency, with which this species is parasitized.W. R. Ingram informs me that he has found two nests of this bird,each containing a single egg of the greater honey-guide in additionto several pecked eggs of the host.Red-shouldered glossy starling, Lamprocoltus nitens (Linnaeus)To the single host record recorded in my book (1955, p. 152) maybe added another, unfortunately without exact data. Mr. C. H.Jerome informs me that he has been told of a second such occurrence,but did not have any explicit information about it.Blue-eared glossy starling, Lamprocolius chalybeiis chalyheus (Hemprich andEhrenberg)The southern subspecies of this starling, L. c. sycobius Hartlaub,was previously known to be parasitized by the greater honey-guide inthe northern Transvaal. We may now note the same for the nominaterace. Mr. W. R. Ingram writes me that at Serere, Teso District,Uganda, on Mar. 22, 1956, he found a nest of this bird containing asingle egg of the greater honey-guide, together with some peckedeggs of the starling.3. Lesser honey-guide. Indicator minorRecent data of interest involve three species of hosts, one of thempreviously unrecorded in this capacity.Striped kingfisher, Halcyon chelicuti chelicuti (Stanley)Previously (Friedmann, 1955, p. 193) I knew of two records, both inSouth Africa. To these may be added a third, somewhat indefiniteone from Kenya Colony, where van Someren (1956 p. 221) found anegg attributed to the lesser honey-guide in a nest of this little kingfisher.Cinnamon-breasted bee-eater, MelittopJiagus lafresnayii oreobates (Sharpe)Van Someren (1956, p. 190) has found this bee-eater to be par-asitized by the lesser as well as by the greater honey-guide in KenyaColony. This is an addition to the known victims.Pied barbet, Tricholaema leucomelan (Boddaert)Previously known as a frequent victim in South Africa, this barbetis now recorded in this capacity in Southern Rhodesia as well, where,according to H. M. Miles (in litt.), Irwin found a nest containing ayoung lesser honey-guide as the sole occupant.
314 PROCEEDINGS OF THE NATIONAL MTJSEXJM vol, losAlthough only of suggestive interest, mention may be made of thefact that in Ghana, between Accra and Kumasi, early in June, DonaldW. Lamm (in litt.) watched a colony of brown barbets, Gymnohuccocalvus, ready to begin breeding. At least four lesser honey-guides(Indicator minor ussheri) were present. They were very quiet,perching on the heavier branches of the trees, and showed no attemptsto enter any of the nest holes. Two of them, a male and a female,were collected, both with well-developed gonads. This observationsuggests that this species of barbet, as well as Gymnohucco bonapartei(already so recorded by Friedmann, 1955, p. 193), may be a host ofthe lesser honey-guide.4. Slender-billed honey-guide, Prodotiscus insignisTo the little known information about the hosts of this honey-guidepreviously compiled by me (1955, pp. 251-252) may be added furtherdetails of the cases there described, as well as one additional hostspecies. Like the previous data, the new observations all stem fromDr. van Someren.Black-throated wattle-eye, Platysteira peltata peltata Sundevall.Of this host all I was able to report previously (Friedmann, 1955,p. 251) was the bare fact that van Someren had once found a para-sitized nest. He (van Someren, 1956, pp. 281-283) recently suppliedmore data, of which the following is a summary. When the nest wasfound, it contained just the young honey-guide, dark brown with ayellow gape, and quite naked. "The chick grew rapidly and on thefourth daj'' of observation was well feathered on the head and back.It was then that I saw that . . . the plumage being graduallyassumed was the olive green of a pigmy honey-guide. . . . Theyoungster was now receiving quite large moth larvae, imago moths,and dozens of small Diptera." Shortly afterwards some predatorrobbed the nest and ended the opportunity for further observation.Kikuyu green white-eye, Zosterops virens kikuyuensis (Sharpe)To the case I previously recorded (Friedmann, 1955, p. 252) merelyas having two young slender-billed honey-guides in the nest, vanSomeren's (1956, pp. 222-223) additional data provide the folloA\'ingdetails. He found one of the young parasites just out of the nest onthe ground near his house. As he was looking to see what nest itmaj^ have come from, he saw one of the white-eyes fly with food to achick in a nest directly above the spot where he had picked up thefledgling. When his son climbed to the nest, the chick in it flutteredto the ground; it was found to be another slender-billed honey-guide.Van Someren put the two young bu*ds in a cage, to which both parentwhite-eyes came with food for the next two days. The next nightit rained very heavily and, as a result, one of the chicks died. The
HONEY-GtHDES?FRIEDMANN 315
other one continued to be fed by the foster parents and was lastseen in a tree nearby with the attendant white-eyes. Van Somerenconcludes his account by stating that the original white-eyes' eggshad been disposed of and that the honey-guide laid more than oneegg in the white-eyes' nest. In view of the relative scarcity of thesehoney-guides, it does seem more probable that the two eggs in thisnest were laid by one hen rather than by two, but this is only aninference. Similarly, we have no knowledge as to whether thehost's eggs were removed by the laying honey-guide or ousted bythe nestlings. In another place in his book, van Someren (1956,p. 434) does state that the hen honey-guide removes the victim'seggs one at a time when laying her own, but he gives no substantiatingevidence for this statement.Amethyst sunbird, Chalcomitra amethystina kalckreuthi (Cabanis)This sunbird is an addition to the known victims of the slender-billed honey-guide. In November 1956, at Ngong, Kenya Colony,G. R. C. van Someren saw a newly fledged young slender-billed honey-guide being fed by both members of a pair of amethyst sunbirds.He watched them for some time at a distance of less than 10 feet.Mammalian SymbiontsIt is well established that the original foraging symbiont of thegreater honey-guide is the ratel or honey-badger, Mellivora capensis,and that the human has deliberately become a substitute symbiont inits place. In my earlier account (1955, pp. 41-50) I gave some datato indicate that very occasionally baboons might be involved, andcited one instance of a bu-d apparently attempting in vain to evokeresponse from a mongoose, Myonax cauui. Verheyen (1951, pp. 91-93;1957, pp. 105-113), on the other hand, suggested that the honey-guidemay attempt to "call" to any or all of the larger mammals, betweenwhich he assumed it could not or did not distinguish. I find it difficultto agree with Verheyen in this matter and look upon the mongooseincident as an occasional error on the bu-d's part. However, the factthat as un-ratel-like a creature as the African human could becomeaccepted as a symbiont shows that there may be a basic symbionttolerance beyond what normally transpires. In this connection, it isof interest to record the following incident involving a greater honey-guide and a genet, kindly sent me by Bryan Neuby-Varty, who madethe observation on his farm near Marandellas, Southern Rhodesia.One day he was out in the brush when he heard a honey-guide callingand wondered if it was calling to any creature. Moving carefully hegot behind a large tree and could see that it was watching a genet(probably Genetta geneita mossamhica) on the ground at a hole at the
316 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io8base of a tree from which swarms of bees were flying. As long as thebird kept calling, the genet remained motionless, but soon it disap-peared up to its shoulders down the hole, apparently not minding thebees. In a short while, it backed out with a small piece of beescombwhich it proceeded to eat. Neuby-Varty then moved to a better posi-tion on a termite mound about 30 yards from the genet, from whichspot he watched it for about half an hour as it repeatedly inserted itspaw into the hole, pulled out pieces of comb, and proceeded to eatthem. Then the wind changed and the genet must have scented theobserver and it slunk off into the tall grass and was gone. Exam-ination of the hole convinced Neuby-Varty that it was not dug by thegenet but may have been the work of a jackal or possibly a mongooseor a ratel, although he has never seen the last named animal on his land.In the above incident, there is no evidence that the bird had guidedthe genet to the hive, which apparently had been opened previously.It is more lilvely that the bird was attracted to the spot because of thebees, and its interest was then transferred to the genet that had comethere independently and which, by virtue of its feeding there, actuallykept the bird from domg the same. After the genet had left, the birdcalled intermittently for about 10 minutes and Neuby-Varty waitedanother 20 minutes to see if the beast would return. In those 30minutes, the bird hopped down to the ground only once and peckedat tiny bits of comb.We still have too few observations of associations between thegreater honey-guide and various mammals, but it does seem that ob-servations such as this one, or the one involving the mongoose, andeven the baboon incident recorded earlier (Friedm.ann, 1955, pp. 45-46), hardly justify looking upon these creatures as definitely provedsymbionts of the bird in the sense that ratels and humans are.The Termination of Guiding BehaviorIn my detailed account (Friedmann, 1955, pp. 25-71) I stated thatthe stimulus which appears to bring to a halt the guiding behavior,released earlier by the bird meeting with a potential foraging symbiontsuch as a ratel or a human, "is the sight or sound of bees. It is tempt-ing to expand van Uexkiill's and Lorenz's fruitful concept of the
'kumpan,' or companion, as the releaser of instinctive actions in birdsand apply it to the honey-guides .... From this standpoint guidingmay be looked upon as the result of the reactions evoked in the birdwhen the releasing agent is met with in the bird's natural environment,away from the bees' nest, for which it is the 'kumpan,' and the 'guid-ing' behavior is 'satisfied' or, at least, brought to a stop when the birdbrings together the 'bee companion' and the bees." While I still think
HONEY-GUIDES?FRIEDMANN 317
this statement is as close to the actual picture as present understandingpermits, it has seemed to me possibly a little forced in its reasoning.It was, therefore, with considerable interest that I recently came across,in Russell's (1953) description of the drive character of instinctivebehavior, some ideas that give further support to the applicability ofthe "kumpan" concept to guiding activities.In the current general theory of instinct, we find that usually achain of actions grouped under one heading as instinctive behaviortends to be divided into two phases, an introductory one of openlyseeking, striving, appetitive behavior, and a directly subsequent oneof essentially consummatory action, generally of a quasi-mechanicalor quite stereotyped nature. The emphasis on the innate drive char-acter of instinctive behavior, developed largely by Lorenz and hiscolleagues, seems warranted.These investigators account for the specificity of the drives by hy-pothesizing what they term "action specific energy," which is said toaccumulate and to be discharged with and into highly specific appeti-tive behavior patterns. Lorenz (1950) further assumes "that somesort of energy, specific to one definite activity, is stored up while thisactivity remains quiescent and is consumed in its discharge." Russellsees no real need to hypothesize energy when all that seems to be
"accumulated" may be described just as readily as "specific tension orunreleased tendency to carry out a certain course of action." Regard-less of whether it is a specific energy or a specific tension, the factremains that we have, in either case, a support for what I implied whenI wrote that the guiding behavior was "satisfied" and brought to ahalt when both the bees and the bee "kumpan" simultaneously cameto be within the sensory range of the bird. The specific energy isdischarged, or the specific tension is dispelled, when the guiding birdachieves the unison of the releasing agent, the foraging symbiont, andthe thing with which the releaser is associated in the experience of theactivated bird, the bees. The mode of termination of guiding is onemore example of the increasingly obvious fact that it is the dischargeof consummatory action and not the biological or sm"vival value in-volved that is the goal of innate appetitive behavior as far as the indi-vidual bird is concerned.The Rustling FlightThe rustling flight, recorded for both the greater and the lesserhoney-guides (Friedmann, 1955, pp. 130-133, 184), is of interest notonly for itself but as the possible root from which evolved the highlyspecialized performance of the lyre-tailed honey-guide, Melichneutesrobustus. The evidence is somewhat divided as to whether the rustling
318 PROCEEDINGS OF THE NATIONAL MUSETJM vol. lossound is produced by the wings or the tail in the greater and lesserhoney-guide species, while in the lyre-tail it seems obvious that thesound is made by the highly peculiar outer tail feathers.Two interesting additional observations have come to me, bothhaving to do with the greater honey-guide. Neuby-Varty writes methat about the end of May, on his farm near Marandellas, SouthernRhodesia, he heard a greater honey-guide giving its victor call from thetop of dead branches of a tree. Then it flew towards him, and just asthe bird came above him, it started to make a rattling noise, appar-ently with its wings. The tail may have been involved as well, as thebird spread it fanwise while making the noise. Neuby-Varty timedthe performance and found the noise (written down as feet-up) wasgiven 10 times, with an interval of about a second between the sounds.W. R. Ingram, at Serere, Uganda, informs me that he has found therustling or drumming flight to be given only towards evening and al-ways in the early dry season. He thinks it has no connection withcourtship, as there are no suitable hosts nesting at the time of the year.He first heard it in December 1955, at about 7 p. m. and almost dark;the noise "was most eerie and seemed to come from different parts ofthe sky almost at once, showing that whoever or whatever was makingthe noise was moving very fast indeed." Ingram describes the soundmade by suggesting that if one blows out the word whukooo with agreat expulsion of air on the first syllable and with strong emphasison the K, and then emptying one's lungs on the ooo, a similar sound canbe produced. He goes on to say that "the noise was heard occasion-ally at dusk dming the whole di-y season (December-March) and againin 1956, but the author was never discovered." It was not until 1957that he succeeded in seeing as well as hearing the performing bird.Early in December of that year, at about 6 p. m., he saw the bird
. . . traveling at a very high speed in a circling, dipping flight. It careenedaround the sky for about 30 seconds and then dived into a large tree ....Immediately, three or four victor notes came from this very tree ....I knew this tree to be a popular stud-post, all the year round, but still I could notconnect the bird in the sky with the honey-guide.However, I did not have to wait very many evenings before I got a repeatperformance. I managed to pick up the bird in flight with the binoculars duringits drumming flight, follow it round and into the same stud-post. At the momentit darted into the tree, if fanned its tail and the outer white feathers were veryconspicuous; this is the only time it opened its tail in flight, so I assume the noiseis done with the wings. It landed on a prominent perch and I got close enoughfor a positive determination ....This account indicates a similarity in habit to the aerial evolutionsof the lyre-tail even more definitely than did our previous data. Italso supports the observations of Ranger, Neuby-Varty, and myselfthat the sound is produced by the wings and not by the tail.
HONEY-GUIDES?FRIEDMANN 319Feeding HabitsThat fair numbers of honey-guides may occasionally gather to eatat a single bees' nest is shown by an observation sent me by H. F.Stoneham, who heard noises coming from one of his domestic beehives.Thinking that a rat or some other creature was raiding the nest, hewent to it, and was surprised to see eight honey-guides fly out in rapidsuccession, six greaters and two lessers.Kettlewell (1955, pp. 45-47) describes a nest of wild bees built in anabandoned wrecked automobile, the metal of which became hot fromthe sun and caused the honey inside to ferment. This apparently hadintoxicated a greater honey-guide, which Kettlewell pulled out of theautomobile.An addition to the known diet of the lesser honey-guide is reportedby van Someren (1956, p. 221), who saw one taking the young larvaeand pupae from the paper nest of an aculeate wasp. This recalls theold observation of Butler, Feilden, and Reid (1882, p. 208) whoreported the greater honey-guide pecking at the comb of a wasp'snest that had fallen to the ground.Chapin has recently sent me some observations on the feeding habitsof the least honey-guide, Indicator exilis, in the eastern Belgian Congo.He opened an old bees' nest in which he found considerable quantitiesof comb, practically empty of honey. The next day a least honey-guide came to it, and again two days later he saw one there. He placeda piece of the comb in a branch of a tall bush where he could watch it,and the bird came there and ate pieces of the comb. The bird wasalone in each case, which fact seems to answer Chapin's (1939, p. 540)earlier statement that since this species does not guide humans, itmay have some other mammalian symbiont.Chapin observed not only the least honey-guide feeding at openbees' nests, but also his newly discovered pigmy honey-guide. Indicatorpumilio. In fact, most of his specimens of the latter were capturedwith a butterfly net as they emerged from a beehive.Recently Verheyen (1957) has taken objection to my conclusionthat the primary interest of the honey-guides in bees' nests is the waxof the comb rather than the honey, pollen, or bee larvae. It should bepointed out that I have described that the birds do eat the bee larvaeand pupae, and, adventitiously, the honey, but it still remains that thewax is the one substance they are most eager to get from the hive, andthe one substance they cannot obtain elsewhere. They are constantlycatching insects on the wing, and are certainly not primarily waxfeeders. As I pointed out, honey-guides grow to full size in their hosts'nests without getting any wax in their food, but once they begin fend-ing for themselves they eat wax avidly, not as a substitute for some
320 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io8
other food but as an addition to their diet. By itself, beeswax is not a
"total" food as it lacks nitrogen, without which no bird could survivefor more than a few weeks or a month.ReferencesBlERENS DB HaAN, J. A.1956. Het honingaanwijzen van de Honingaanwijzers. Ardea, vol. 44, pp.289-293.Butler, Edward A.; Feilden, Henry W.; and Reid, Saville G.1882. Ornithological notes from Natal. Zoologist, ser. 3, vol. 6, No. 66,pp. 204-212.Chapin, James P.1939. The birds of the Belgian Congo, II. Bull. Amer. Mus. Nat. Hist.,vol. 75, 632 pp.Fribdmann, Herbert.1955. The honey-guides. U. S. Nat. Mus. Bull. 208, 292 pp.Jackson, Frederick John.1938. The birds of Kenya Colony and the Uganda Protectorate, vol. 2, pp.545-1134.Kettlewell, H. B. D.1955. Note. Entomologist, vol. 88, No. 1101, pp. 45-47.LORBNZ, KONRAD1950. The comparative method of studying innate behaviour patterns inphysiological mechanisms in animal behaviour. Soc. Exp. Biol.Symposium 4, pp. 221-268.Roberts, Hugh A.1956. Breeding tactics of the two honey-guides
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Indicator indicator(Sparrman) and Indicator minor Stephens. Bull. Brit. Orn. Club,vol. 76, p. 114.Russell, E. S.1953. The drive character of instinctive behaviour. Arch. N6erlandaisesZool., vol. 10, suppl. 2, pp. 110-120.Serle, William1957. A contribution to the ornithology of the eastern region of Nigeria.Ibis, vol. 99, pp. 371-418, 628-685.Smithers, Reay H. N.; Irwin, Michael P. Stuart; and Paterson, Mart L.1957. A Check List of the Birds of Southern Rhodesia. 175 pp.VAN Someren, V. G. L.1956. Days with birds. Fieldiana, Zool., vol. 38, 520 pp.Vbrheyen, Ren]6.1951. Contribution It I'^tude 6thologiques des mammifferes du Pare nationalde rUpemba, 161 pp.1957. A propos du comportement 6trange de "I'Oiseau k miel." Le Gerfaut,vol. 47, pp. 105-113.
U. S. COVERNHENT rRINTINS 0FriCItl9lt