Courtship Feeding in Birds 169

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VoL,94057] a l_•caz,Courtship Feeding in Birds 169

COURTSHIP FEEDING IN BIRDS

BY DAVID LACK

INTRODUCTION IN many differentgroups of birds the male feedsthe female during courtshipor incubation. The literature on this point is large and scattered. The objectof the presentpaper is to summarizethe data so far as I have been able to collect them. So many instanceshave been reportedin worksdealing primarily with other mattersthat I cannothope that the presentlist of birdsis nearlycomplete. Indeed, one of the objectsof this paper is to stimulate others to record in- stancesfrom typesof birds not recordedhere. Someyears ago cor- respondentsof 'The Auk' greatly increasedour knowledgeof the extentof' injury-feigning'in birdsand in this,as in courtshipfeeding, an accurateknowledge of all thosegroups in which it occurs,and also of thosein which it doesnot occur,greatly assistsin interpretingthe significanceof the habit. Beforepublication, I am sendingthis paper to Mrs. Margaret M. Nice with the requestto add all the casesthat shemay know from her unrivaled knowledgeof the literature of bird courtship. Indeed,should the Europeansituation make it impossible for me to seethe proofsof the paper,I am askingMrs. Nice to super- visepublication. i must alsothank Dr. E. Mayr and Dr. G. K. Noble for their help in discussion.

MANNER OF FEEDING In mostcases of courtshipfeeding, the femaleadopts an attitudeand callsalmost identical with thoseof a youngbird beggingfood from its parents,and the male puts food into the œemale'smouth. x In some birds,the male simplycollects the food in his beak and then presents it to the œemale;in others,notably in someFringi1Iidae (i.e. Car- duelinae)and gulls, the male regurgitatesthe food to the female, as he alsodoes when feedingthe young. While this is the normal pro- cedurethere are a few variations. Thus in the Herring Gull and other gulls, the male regurgitatesthe food on to the ground in front of the female, and the female then swallowsit. In terns, presentationof food is often precededby a ceremonialflight. In somebirds of prey,

• Monika Holzapfel in her 'Analyse des Sperrens, und pickens in der Entwicklung des Stars' (Journ. f. Ornith., 87: 5•5-553, '959) suggeststhat 'gaping' for food is not merely a juvenal phenomenon,but that it is replaced by the tendencyto peck for food, and becomeslatent, reap- pearing later in those specieswhere the male feeds his mate.--M. M. N. 170 LACK,Courtship Feeding inBirds I.[' AukApril notablyCircus, the food is passedfrom the male to the femalein the air, the female turning over to catch it. In the Ad61iePenguin (Pygoscelisadeliae) the male brings not food but snow to the incu- bating female. Dr. Mayr drawsmy attention to Gallus gallus domesticus,which does not presentthe femalewith food, but scratches the groundup for her (asa hen doesfor her chicks).

T•-IE R6ta•s ov X•-IE SEXES In nearly all birds it is the male which feedsthe female. The re- spectiver6les of the two sexesare almostas constantas are the posi- tions adoptedin copulation. A partial exceptionis the waxwing (Bombycilla),in which male and femaleexchange food backwardand forward, but it is again the male which first presentsand the female whichfirst receives the food. ! onceobserved the samein Platyspiza crassirostris,one of the Galapagosfinches, but here it is very unusual, and! haveseen it once (out of hundredsof cases)in the BritishRobin (Erithacusrubecula melophilus), when the birds were disturbedby a mount near the nest. In one bird, the Button Quail, Turnix, the normal procedureis reversedand the femalefeeds the male. This wasperhaps to be ex- pected, since in Turnix nearly all the sex behavior is reversed. In Common Terns (Sterna hirundo), Tinbergen recordsthat, in the early stages,either sex may beg for or presentfood. Under artificial conditionsin captivity,I have had a female British Robin feed another female, and a male beg food from a female. Why, normally,the male shouldgive the food and the femalere- ceive it, and not the reverse, is far from clear. The occurrence of the oppositein Turnix, whereother sexbehavior is alsoreversed, is con- firmation that there is a fundamental distinction between male and femalein this matter. Possiblyit is relatedin someway to the phe- nomena classified under the term 'dominance,' but ! am not too happyas regardsthe useof this latter term owingto its subjective implications. The captivity recordsof the British Robin show that the behaviornormally found in one sexis latent in the oppositesex (this seemsto apply to all phasesof sexualbehavior in birds).

SIGNIFICANCE OF THE FEEDING In many speciesin which courtshipfeeding occurs, the male also feedsthe femaleon or near the nestduring incubation. Hence,at thisstage of the breedingcycle, the foodmay have real significance. Vol.•04o57 •] LACK,Courtship Feeding inBirds 171

Indeed, there probablyexist speciesin which the feedinghabit is restrictedto the incubationperiod. In this case,it could not be classedas courtshipfeeding at all. I know of no fully established cases,but thismay well occurin someof the speciesgiven in the table laterin whichthere are records of feedingonly during incubation, e.g., sometitmice (Paridae),some finches (Fringillidae), some crows (Cor- vidae). However,there are alsosome species, e.g., Aix sponsa,Gallus and Turnix (? alsoCentropus and Coccyzus)in whichthe feedingof thefemale by the maleoccurs in courtshipbut apparentlyceases before incubation. Further,in manyof the speciesin whichthe male feeds thefemale during incubation, feeding is alsoregular before incubation and in somespecies, e.g., the British Robin, it is much commoner beforethan duringincubation. Hence,in theselatter birdsthe main functionof courtshipfeeding is clearlydisplay. Clearlythe primaryobject of courtshipfeeding is not the foodwhich is passed.Numerous cases could be citedto showthis. I mayquote Goethe0937), that a femaleHerring Gull (Larusargentatus) just returnedfrom feedingon the shore,and, therefore,presumably well fed, may beg her mate for food although he has remained near the nest and has not fed recently. Again, in captivity a female British Robin would often beg her mate to feed her thoughshe was standing on the food tray, surroundedby live mealworms,and he was some distanceaway. Again, in Bombycilla,the food is passedback and forth betweenthe sexesand finally is often eaten by the male. In somespecies, courtship feeding seems closely associated with copulation. Thus, in Centropusjavanicus the male holdsan insectin its beak during copulationand feedsthe femaleimmediately after- ward. In the Yellow-billedCuckoo (Coccyzus americanus), the male alsoheld an insectduring copulation, and, towardthe end,the female slowlyturned her headand took and ate it. In Carnarhynchuspar- vulus,one of the Galapagosfinches, Mr. W. H. Thompsonsaw the malefeed the femaleduring copulation. Again,in the Herring Gull, Goetherecords that the initiatory stagesof copulationare closelysimi- lar to thoseof the male feedingthe female. In Columbalivia, the male feeds the female before copulation. In the European Nut- hatch (Sitta europaea),courtship feeding and copulationare also saidto be correlated,and this may be the casein Gallusgallus domesticus. The associationof courtshipfeeding with copulationin the above speciesseems clear, and thisapplies to someother species. However, 172 LACK,Courtship Feeding inBirds LAprilFAuk there are other birds in which there is no connection between courtship feedingand copulation. This is clearly the casein the British Robin, in which courtshipfeeding and copulationoccur quite inde- pendently,and whereascopulation is restrictedto a very limited period duringnest building and egglaying, courtship feeding occurs throughout the breedingcycle except when the birds are feeding the young. This was alsotrue for the Galapagosfinches except for the one case in Carnarhynchusparvulus, already reported (D. Lack and W. H. Thompson);it applied to Spinuslawrencei (D. Lack) and evidently appliesto manyother species,since the observers•make no recordsof any connectionwith copulation. Further data are desirablebut it seemsprobable there are more speciesin which the habit is not con- nectedwith copulation,than thosein which it is. The functionof courtshipfeeding in the latter formsis presumably to maintainthe bond betweenthe pair, whichis especiallyimportant in birds in which both sexesfeed the young. In this connectionit seemssignificant that courtshipfeeding is found mainly in birds in whichboth sexescare for the young. This is especiallysignificant in thosegroups of birds which includeboth somespecies which remain paired,and somewhich do not form a pair bond. Thus, in the gallinaceousbirds, the Bob-white(Colinus virginianus) remains paired and courtshipfeeding occurs, whereas it doesnot occurin the many gallinaceousbirds where no pair bond is formed. Again, in the cuckoos (Cuculidae),it occursin Centropusand Coccyzus,but not (so far asknown) in the parasiticforms. There are,however, exceptions to this rule. Thus in Turnix, the female leaves the male soon after incubation has commenced.

OTHER FEEDING HABITS This habit of onebird feedinganother seems normally part of courtship. However,two casesare reported by Murphy in whicha Fregata rnagnificensand an adult Brown Booby (Sula leucogaster)at least four yearsold, were found in perfectcondition at breedingcolonies, althougheach possessed only one wing and couldnever have captured food for itself. Both birdsapparently retained the food-beggingbe- haviorof the youngand were maintainedby other membersof the colony. That thebegging of foodby a youngbird exercisesa strong attrac- tion on adultsis alsoillustrated by the not infrequentoccasions on whichpassing birds havefed a fledglingEuropean Cuckoo (Cuculus Vol.194o•?-] a LACK,Courtship Feeding inBirds 173 canorus)or Cowbird (Molothrusater) rearedby other fosterparents. Possiblyparallel are the casesreported by Skutchof individualshelp- ing to feeda broodof young. In EuropeanSwallows (Hirundo rusti- ca), the Moorhen, (Gallinula chloropus)and the Bluebird (Sialia) (see Laskey,Bird-banding, 6: 23-3•, 1939), the young of the first broodmay evenhelp to feed the secondbrood. The occurrencesof theseinstances divorced from any courtshipdis- play make it easierto understandhow the feedinghabit could have becomeincorporated into display.

SYMBOLIC NATURE OF THE HABIT

Sincethe main functionof courtshipfeeding is not food, it might be classifiedas a typeof 'symbolic'display, i.e., in whichan act normally playing someother part in bird behavioris introducedinto display. Habit preening,and the manipulationof nestmaterial are otherexamples. In manyspecies (but certainlynot all, Wood Duck (Aix sponsa),and Turnix are presumablyexceptions and soprobably are thosespecies where courtship feeding occurs primarily in connection with copulation)feeding may have been introducedinto the sexualcycle through an extensionback into an earlier phaseof the cycleof the habit of feedingthe femaleduring incubation. In this it closelyparallels the 'displaybuilding' of the Galapagosfinches and otherbirds, in whichbuilding and manipulationof nestmaterial are a prominentfeature of courtship,but the eventualfunctional nest is often built at a later stage. In birds, many instinctiveacts are ex- hibitedin a partiallydeveloped form beforethe biologically'correct' momentarises, and thisphenomenon would supply the initial element on which selection could later work. In somecases, courtship feeding is reducedto an incipient act. Thus,billing occurs in theMourning Dove (Zenaidura macroura), the EuropeanKingfisher (Alcedo atthis), the Rook (Corvusfrugilegus), the Chough (Pyrrhocoraxpyrrhocorax), the Waxwing (Bombycilla), and someFringillidae, e.g., Hawfinch (Coccothraustes),the Siskin (Carduelisspinus), Geospiza, and other species;also in PeregrineFal- cons( Falcoperegrinus), which touch beaks in the air. In thesebirds billing can be regardedas incipient courtshipfeeding. It should be noted that in someother birds, e.g., herons,billing has probably not developedfrom courtshipfeeding but possiblyfrom the passing of nest material from the male to the female. In yet others, e.g., 174 LACK,Courtship Feeding in Birds [[April Auk Fulmar (Fulmarusglacialis), billing has clearlyoriginated from neither of these acts. The 'fish flights'of ternsmay alsooccur without any exchange of food. This habit, like billing, may, therefore,be regardedas symbolicof courtshipfeeding, which is itselfa symbolicact. In the BlackSkimmer (Rynchops nigra), Pettingill has recorded a malepre- sentingthe femalewith driftwoodinstead of the usualfood (presum- ablybecause the male had no foodavailable at thetime).

OCCURRENCE OF COURTSHIP FEEDING Sofar asis known, birds are the only vertebrates which exhibit courtshipfeeding (omitting the sporadicoccurrences in humanbeings). However,it rathersurprisingly occurs in one othergroup of animals, namely,the dipterousflies of the familyEmpidae. In the latter,it seemsassociated with inducingthe femaleto copulateand, interest- ingly enough,in somespecies the courtshipfeeding is symbolicin that no real food is passedbut varioussubstitute objects are used (O. W. Richards,Biol. Rev.Cambridge Phil. Soc.,3: 398-360,•937). Courtshipfeeding occurs in so many widely separatedgroups of birds that it has almost certainly originatedseveral times inde- pendently.Particularly striking in this respectis its occurrencein onespecies of duck,in just a few gallinaceousbirds, in onespecies of wadingbird, and in Tropic-birdsbut no otherPelecaniformes. There are alsospecies, e.g., Chiffchaff,Wood Warbler (Phylloscopusspp.), Tree Pipit (Anthustrivialis) and Bluebird (Sialiasialis) in whichthe habit is only rarely found and in which many individualsapparently do not show it. Further,the survey,given below, of the speciesin whichmale feeding female occurs,shows that it playsa rather differentpart in the lives of different speciesand may have originated in different ways. Thus, in somespecies it occursprimarily (possiblyexclusively) during incubation. In other speciesit is regularduring incubationbut com- monerbefore it. I had thoughtat first that the habit might be restrictedto birdsin whichonly the femaleincubates, e.g., manyfinches, titmice, crows,and others. Further study showsthat this is by no means the case. Prominent exceptionsare the gulls (Larus), terns (Sterna),pigeons (Columbidae) and others. There are even species in which courtshipfeeding occurs although one sex leavesthe other at incubation. Further, many passerinegroups in which only the femaleincubates do not exhibit courtshipfeeding. Again, there are Vol.•04o57] J I•½I•,Courtship Feeding inBirds 175 speciesin which the habit seemsclosely linked with copulation,and others in which it has no connection with this. in Red-backed Shrike (Laniuscollurio) it seemscorrelated with both copulationand incubation. All thesepoints should be bornein mind by futureobservers. In the followinglist it is seenthat courtshipfeeding is sometimes typicalof a wholefamily of birds,while in othersonly one or two generain a familymay show it. (! knowof no caseswhere two species of the samegenus differ.) In the following list I follow the order and classificationof bird familiesproposed by Wetmore(2934) and record those forms in which courtshipfeeding has been found, and also thoseforms which have been studiedsufficiently for one to be fairly certain that the habit doesnot occur. If the word 'incubation'is written after the species, it meansthat the habithas as yet beenrecorded only duringincubation. This should not be taken to mean that the habit is confined to incubation,as courtshiphabits have been studied much less than nestinghabits. I have omittedaltogether certain tropicalfamilies aboutwhich nothingis known,and have been unable to coverthe Australianand New Zealandliterature. I hopesome reader of 'The Auk' may be able to do this.

CLASSIFIED LIST P,•L•,•O•,'rH• (struthiousbirds). Apparentlyabsent. SeHE•SC•gORMES(penguins). Ad•lie Penguin(incubation) brings snow. G•,VngORMES(loons). Absent. COLYMB•gO•S(grebes). Absent. P•OC•,•ngO•M•S (petrels, etc.). Absent so far as known; certainly absent in Fulmarus. Pg•CA•gOR•S (tropic-birds,pelicans, frigate-birds, cormorants, boobies). Found only in tropic-birds. Cmo•IgO•gs (herons,etc.). Absent. A•s•go•s (geese,ducks, swans). Normally absent;occurs in ,4ix sponsa. FA•CO•gO•M•S(birds of prey). Regular in Circus (correlatedwith a specialflight, the 'pass')and Falco spp., e.g. peregrinus,subbuteo, sparverius, aesalon; also recordedin ,4ccipiter nisus,Milvus migrans,Haliaeetus albicilla, and (unusually) Aquila chrysiietos.In mostof the above,it hasbeen recorded only during incubation, but definitely earlier in Falco peregrinus,F. sparverius,F. columbarius aesalon,and Circuspygargus. G•L•goR•gs (gallinaceousbirds). Normally absent,regular in Colinusvirginianus; occursin Gallusgallus domesticus. Ggr0•gog•gs(cranes, rails, etc.). Regular in Turnicidae (buttomquails),where female feedsmale. Recordedduring incubationin Rallus aquaticus,and by one observerin Gallinula chloropus;possibly not regular in the last, sinceit is not mentionedby most observers. 176 LACK,Courtship Feeding in Birds LApril[' Auk

CHARADRIIFORiM[ES(a) Charadrii (shorebirds). Normally absent, but recordedin Burhinusoedicnemus (Stone Curlew). (b) Lari. In the Laridae,regular in all speciesof Larus(gulls) and Sterna (terns) so far studied,in the formerby regurgitation, in the latter associatedwith a 'fish flight.' Recordedin Bynchopsnigra (BlackSkimmer), but apparentlyabsent in the third family of the Lari, the Stercorariidae(skuas, jaegers). (c) Alcae (auks). Apparentlyabsent. COLUMBIFORMES(pigeons, doves, etc.). Regular,by regurgitation,in Zenaidura, Columba,Ectopistes, Turtur, and presumablyother generaof the Columbidae. PSITTACIFORMES(parrots). Recorded in captivePsephotus and Platycercus. Mr. Karl Plath of the BrookfieldZoo informsus that this is regular in all parrots;in homo- sexualpairs it may be exhibitedby females. CUCULIFOR•{ES(cuckoos, etc.). Recordedin Centropusand Coccyzus;apparently absent in parasitic forms. STRIGIFORMES(OWLS). Recorded in a captivepair of Otusasio (ScreechOwl); other speciesprobably not sufficientlystudied. CAPRIMULGIFORMES(nightjars). Apparentlyabsent. MICROPODIFORMES(swifts, hummingbirds). Apparentlyabsent. CORACIIFORMES(kingfishers, bee-eaters, rollers, hornbills). Recordedin ,,11cedoarthis (EuropeanKingfisher), also Upupa epops (Hoopoe) (incubation)and hornbills (incubation). PI½IFORMES(woodpeckers, jacamars, toucans,barbets). Recorded in Galbula melanogenia(jacamar). Apparently absentin Picidae (woodpeckers),though 'billing' has been recordedin Campephilus. PASSERIFORMES(treated under families,and numerousfamilies for which there are no positiveor negativedata are omitted): Tyrannidae(tyrant flycatchers).Regular in Pyrocephaluson the Galapagos Islands(personal observation, also W. H. Thompson).Have found no otherrecords. Pittidae (pittas). Recordedin Pitta cucullatain captivity. Pipridae (manakins).Clearly absent in Manacusvitelllnus. .4laudidac(larks). Recordedonly in Lullula arborea(Niethammer, •: •59, •937). Hirundinidae (swallows). Apparently absent. Corvidae. Regularin Corvusspp., e.g., corax,corone, frugilegus (for all of these ! have found referencesonly to incubation), Coloeusmonedula (Jackdaw)and Pyrrhocorax(Chough) including before incubation; also Pica (magpies)and various jays,i.e., probablyfound throughout the family. Paridae (titmice). Recordedin mostWest Europeanspecies of Parus (major, caeruleus,atricapillus, ater, cristatus) also Penthestes a. atricapillusin North America during incubation. Sittidae (nuthatches).Regular in Sitta europaea,canadensis and carolinensisin courtship and incubation. Certhiidae(tree creepers).Regular in Certhiafamiliaris. Chamaeidae (wren tits). Absent. Cinclidae (dippers). Regular in Cinclusaquaticus. Troglodytidae (wrenS). Apparently absent. Mimidae (thrashers, mockingbirds). Apparently absent. Turdidae (thrushes,etc.). Apparently absentin Turdus, also in Saxicolaand Oenanthe. Regular in Erithacus rubecula (European Robin), occasionalin the Bluebird (Sialia sialis) and Myadestestownsendi (Townsend'sSolitaire) (personal observationof R. T. Orr). vo•.**'l•04oa LACK,Courtship Feeding in Birds 177

Muscicapidae(Old World flycatchers).Recorded in Muscicapastriata and M. hypoleuca(incubation). Sylviidae(Old World warblers). Recordedin Acrocephalusscirpaceus and (as an abnormality)in Phylloscopuscollybita and P. sibilatrix;seems normally absent. Prunellidae (accentors).Occasional in Prunella modularis(Hedge Sparrow). Motacillidae(wagtails, pipits). Seemsabsent in wagtails,and usuallyabsent in pipits, but recorded (as an abnormality)in Antbus trivialis. Bombycillidae(waxwings). Regular in Bombycillacedrorum and B. garrulus. Laniidae (shrikes). Regularin Laniusludovicianus, recorded in L. collurio (both precedingcopulation and in incubation)and L. senator(the last, in incubation). Sturnidae (starlings). Absent. Vireonidae(vireos). Not recorded. Compsothlypidae(wood warblers). Recorded in Dendroica aestiva, castanea, caerulescens,and pinus, and Protonotariacitrea. Ploceidae(weaver finches). Not recorded. Icteridae(blackbirds, troupials, etc.). Neverrecorded, though several species have been studied in detail. Thraupidae(tanagers). Recorded in captiveCalospiza thoracica. Fringillidae (finches). Regular in many genera,including Richmondena (Cardi- nal), Coccothraustes(Hawfinch), Chloris (Greenfinch),Carduelis (EuropeanGold- finch,Lesser Redpoll, Siskin), Spinus (Americangoldfinches), Pyrrhula (Bullfinch), Pinicola (Pine Grosbeak),Leucosticte (Rosy Finch), Loxia (crossbill),Fringilla (Chaffinch),Plectrophenax (Snow Bunting) and all the Geospizinae(Galapagos finches). In someof theseit has been recordedonly during incubation,but in most (not, apparently, the Chaffinch)it also occursbefore incubation. Typically, seems absent in buntings and American sparrows,including the well-studiedEmberiza (Yellowand Reed Buntings),Zonotrichia (White-crowned Sparrow), and Melospiza (SongSparrow). REFERENCES It seemsbetter to depart from the usual customand list the refer- encesin systematicorder of the birds, not of authors' names. To save space,titles of papersare also omitted, but the name of the species referred to is retained. Generalre[erences.--Records for many European species are foundin 'The Handbookof BritishBirds,' •938-39, ed. H. F. Witherby,sections by B. W. Tucker and F. C. R. Jourdain;and in 'Handbuchder DeutschenVogelkunde,' •937-38, ed. G. Niethammer. Specieslisted in these books are not included below. Otherreferences (in systematicorder): Pygoscelisadeliae. Murphy, K. C., OceanicBirds of SouthAmerica, •: $4o, •936- Sula leucogaster,Fregata magnil%ens("permanent infantilism"), ibid.: 795-796. Phiiethonlepturus (Tropic-bird), ibid.: 8o5. Aix sponsa.Heinroth, O., Die BrauenteLampronessa sponsa (L.), Falconiformes. Severalreferences in Bent, A. C., 2937-8, Life Histories of North AmericanBirds of Prey, •. Bull. U.S. Nat. Mus., no. •67: •, •68. Colinusvirginianus. Stoddard,H. L., The BobwhiteQuail, •5-•o, 2936. Turnix lepurana. Butler, A. G., Avic. Mag., (•) 3:•7 -•, •9o5ß FAuk 178 LACK,Courtship Feeding in Birds LApril

Turnixvaria. Seth-Smith,D., Ornis,14:663-675 (Proc. 4th Int. Orn.Congr.), 19o 5. Rallusaquaticus. Zimmerman, R., Mit. saechs.Vet. Orn.,5: lO5-•, •937. Gallinulachloropus. Holstein, V., Dansk.Orn. Foren. Tids., 32: 31-49, 1938. Burhinusoedicnemus. Banzhaf, W., Journ. f. Orn., 81: 311-321,•933. Larusargentatus. Goethe, F., Journ.f. Orn.,85:•-•19, 1937(also many other authors). Sternahirundo. Tinbergen, N., Ardea, 21:1-13, 1932 (also many other authors). Rynchopsnigra. Pettingill,O. S.,Auk, 54: 237-244,•937. Turtur risorius.Craig, W., Journ.Comp. Neut. Psych., •9:29 -8ø, •9ø9ß Zenaidura,Ectopistes. Craig, W., Auk, 28: 398-4o7,•9•. Golumbalivia. Lorenz,K., Journ.f. Orn., 83, 1937. Psephotus,Platycercus. Hampe, H., Journ.f. Orn.,86: 33o-344, 529-543, •938 (also other papersby aviculturists). Centropusjavanicus. Spennermann, A., Beitr.z. Fortpfl.-biol.d. V6g.,4:•39-•44 , 1928. Coccyzusamericanus. Thomas, A.M., Abstr.Proc. Linn. Soc.New .York, •93•-32, nos. 43, 44:46-47 , •934. Otus asio. Bent, A. C., Life Historiesof North AmericanBirds of Prey II, Bull. U.S. Nat. Mus., no. •7o: 243, •938. Bucerotidae(hornbills). Moreau, R. E., Proc.Zool. Soc. London, 33t-346, 1937. Galbulamelanogenia. Skutch, A. F., Auk, 54:•35-•46, 1937- Pitta cucullata. Delacour,J., Proc.8th Int. Orn. Congr.,717-7•9, 1938. Penthestesa. atricapillus. Thoms, C. $., Bird-Lore, 29: 191, •927ß Sitta canadensis. Gunderson, A., Condor, 41: 259-26o, 1939. Sitta carolinensis.Wayne, A. T., Birds of South Carolina,•9o-191, 191o. Sialia sialis. Smith, W. P., Bird-Banding, 8: 25-3o, 1937. Acrocephalusscirpaceus. Howard, H. E., The BritishWarblers, 19o7-14. Bombycillagarrulus. Berndt, R., Beitr.z. Fortpfl.-biol.d. VOg.,9: 138,1933' Bornbycillacedrorum. Crouch,J. E., Auk, 53: •-8, 1936. Lanius ludovicianus. Miller, A. H., Univ. Calif. Publ. Zool., 38: •931. Lanius collurio. Jourdain,F. C. R., Brit. Birds,29: 95-97, •935. Protonotaria citrea. Walkinshaw, L. H., Bird-Banding, 9:41, 1939. Dendroicaaestiva. Linsdale,J. M., Amer. Midland Nat., 19: 12o,t938. Dendroicacaerulescens. Harding, K. C., Auk, 48: 516, •931. Dendroica castanea. Mendall, H. L., Auk, 54: 429-439, 1937. Dendroica pinus. Nice, M. M., Birds of Oklahoma, •6o, •931. Calospizathoracica. Steinbacher, G., Beitr. z. Fortpfl.-biol.d. V6g., 14:81-83, 1938. Richmondena cardinalis. Ganlet, A. F., Wilson Bull., 49: 15-16, 1937. Leucostictetephrocotis. Twining, H., Condor,4o: 246-247, 1938. The SeniorSchool, Dartington Hall Totnes,England