190 wroRr, ThePalate in Icterid,e. [AprilAuk article of 1884,the Sparrow,as a migrant, has becomewell known to ornithologists. Its narrowmigration path, the centerof which in the United Statesis approximatelydown the 96th meridian,has been worked out; the wide extent of territow coveredby strag- glershas beenfully reported;• the food habits of the bird while on migration have been thoroughlyinvestigated and the results published;2 the nesthas beenseen once, s and youngjust out of the nest have been collected,4 and the generalregion of the breeding grounditself is known to be where barren tundra meetsthe edge of the timberbetween Hudson Bay and Great Bear Lake. But the eggsyet remain to be discovered.

NOTES ON THE STRUCTURE OF THE PALATE IN THE ICTERID_/E.

BY ALEXANDER WETMORE.

TttE curiouskeel-like, angular projectionfound on the palate in the North 'AmericanGrackles of the genusQuiscalus, recognized as one of the prominent charactersdistinguishing that group of Blackbirds,is a structurethat can hardly fail to attract attention when the mouth is examinedin freshly killed specimens,or in birds preservedin spirits. Recently, certain observationsmade in the field on these birds, which will be recounted later, recalled this structure to mind and the writer was led to make a somewhat detailed study of the palatal keel in the Grackles,and finally to examinethe appearanceof the palate in other membersof the family Icteridoe. In these studies, carried on in the United States National

• The Status of the Harris's Sparrow in Wisconsin and Neighboring States. By Alvin R. Cahn. Bull. Wis. Nat. Hist. Soc., Vol. XIII, No. 2, pp. 102-108. Also in numerous lists and field notespublished in ' The Auk,' ' Wilson Bull.' and the other bird .iournals. 2 The Relation of Sparrows to Agriculture. By Sylvester A. Judd. Bull. Biol. Surv. No. 15, 1901. s Bird Records from Great Slave Lake Region. By E. T. Seton. The Auk, 1908, p. 72. aBiological Investigation of Hudson Bay Region. By E. A. Preble. N.A. Fauna No. 22. Washington, 1901. Vol. 1919X_XXVI] J WETMORE,The Palate in Icte•idce. 191

Museum, there have been availablesuitable specimens represent- ing all of the leading generawith the exceptionof Clypeicterus, Ocyalus,Lampropsar and Macragelceus.In all, one hundredand thirteen speciesbelonging to thirty-one generahave beenexamined. Study of skinsof the genusQuiscalus shows that the palatal keel is developedas a compressedprojection from the roofof the mouth, slightly behind the center of the commissure(Fig. 1). Viewed

%

Fig. 1. Head of Quiscalusquiscula aeneas. a Palatal keel (about natural size.) from the sideit is truncatedin front, formingan angularprojection that has a tendencyto becometoothed at the tip. Posteriorlyit lowers to mergefinally into the level of the palate. The anterior margin is sharp,and the posteriorportion is thicker and stronger. The entire ridge is developedas a fold in the horny sheathingof the palate, and the surfaceof the premaxillaunderneath is smooth and fiat with no indication ot a bony ridge to supportthe keel. From the examinationof museumskins it appearsthat the palatal ridge beginsto developin juvenile birds a short time beforethey leave the nest, at a stage when the body is well coveredwith feathers,and the incomingtail teathershave attained a length of 20 to 25 millimeters. In such birds the keel appearsas a very slightly raisedridge that forms a distinctline on the palate. The bill at this time has reachedabout three4ourthsof the length attained when the bird is adult, so that the beginningot this ridge appearsto be located far totward, though it occupiesthe same positionin relation to the external nasal openingthat the tully developedkeel doesin the adult. In the dried skinsthe ridge is somewhatindistinct, but it is possiblethat it may be morereadily apparentin livingor recentlykilled specimens. 192 wrT•oar,The Palate in Icteridaz. [April[ Auk

In birdsthat arealmost fully feathered and that areabout ready to leavethe nestthe bill has becomestronger, the raisedpalatal line is heavier, and has a roundedanterior end that forms a masked projectionand then continuesto mergewith the palate in front. In olderspecimens, able to fly but with the rectricesonly 95 to 105min. long,the palatalridge was better marked, being broad and strongbasally and moreslender toward the point. In a few of the specimensof this stageexamined the cuttingangle seemed well developed,but in othersit was lessstrongly indicated. In birdsthat werefully grownbut still in juvenalplumage the ridge was wall developedbut not so prominentas in adults. In some the basalportion was broadand rounded,verging toward the formationof palatefound in the genusMegaquiscalus. In others the anteriorcutting angle was more prominent but theentire ridge hadonly attained from one-half to three-fourthsof its full height. No oneapparently has raised the questionof thepossible function of thiskeel, developed as describedabove, so that it seemsproper to recordhere certainfield observationsmade by the writer that indicatethe useof this structure. As might be expectedit serves in securingand preparingcertain parts of the food. In December 1917,near Stuttgart in easternArkansas, during a time when the ground was coveredby a light fall of snow, flocks of Bronzed Grackleswere found feedingamong small grovesof a pin oak (Quercusp&godaefolia). The groundunder thesetrees was nearly bare and the birdswere workingabout searchingfor the small acornsthat had fallen and were partly concealedunder leaves and low plant growthbeneath the oaks. The Grackleswere tame and with a pair of binocularsit wasan easymatter to watchthem at closerange. The acornswere pickedup, held in the bill and pressedfirmly againstthe keel on the palate,then released, turned slightlyby meansof mandiblesand tongue, and then again gripped strongly. In this way the acornwas rotated until a line had been impressedentirely around the shell. With a little furthermanipu- lation the shelldropped off in two halvesand the kernelwas swal- lowed entire without further preparation,though frequently it wasgulped down only after someeffort. After watchingone feed- ing flockfor sometime I clappedmy handssharply to startlethem and then examinedthe ground where they had been at work. Vol. 1919XXXVI l• WETMORE,The Palate 'in Icterid•e. 193

Scatteredamong the leaveswere many acornshells, most of which had beencut in two in a line transverseto the longitudinalaxis. Some had fairly smooth,clean-cut margins,while others were toughenedand jagged. In searchingthrough the leavesI picked up oneacorn still intact that had beendropped by oneof the birds, perhapswhen the flockwas frightened up, in whicha line had been impressedentirely aroundthe center. In this the impressionsof the palatal keel were distinctlyvisible. When attentionwas onceattracted to this mannerof feeding otherincidents were noted in whichthe palatalkeel was brought in play. On one occasionon the streetsof WaShingtona Purple Gracklewas observedattempting to split opena kernel of corn droppedfrom somepassing dray. The bird heldthis grainin the slightnotch near the centerof the bill and pressedit againstthe angularkeel. The grainproved refractory, as it snappedout sev- eral times, dropping8 or 10 inchesaway, to be seizedand again compressed.Watching until it had been droppedI frightened the bird andsecured the kernelof corn. On oneside four grooves impressedin the hard outer surfacewere visible showing where, andwith whatforce, the sharpkeel had beenapplied. Apparentlythe palatal ridge developswith the gradualgrowth of the bill, andbecomes fully functionalshortly after the immature bird is left by its parentsto its own resourcesin securingfood. It seemsto be fully grownin all by the middleof September. In many adult specimensthe ridge showssigns of heavy wear from the nearly constantuse to which it is put. In somethe cutting angle was well roundedin front from constantabrasion, while in othersthe anteriormargin had becomeirregular and broken. In one specimenthe thin lower margin of the compressedkeel was entirelyworn away, leavinga low roundedprojection in whichthe two sidesof the fold by which the keel had been formed were clearly visible,with a line of separationbetween them. It was interestingto note that the palatal ridge was usually well worn in old adults,taken in late fall or early spring,belongrig to the northernraces (Quiscalus q. quisculaand Q. q. ozneas)while little or no wear wasapparent in similarspecimens of the southernform (Q. q. agkeus)from South Carolinaand Florida. The data avail- able from the examination of a small number of stomachs of this 194 ThePalate in Icteridc•. œApri[ Auk form from Florida showa preponderanceof insects and fruits with very little mast or grain, a fact of interest, but one that is not fully substantiatedas the material available is small. Among near relatives of Quiscalusquiscula a slightly developed palatal ridge was encounteredin Megaquiscalusmacrourus, where the projectionwas broad and well roundedposteriorly, and narrow in front with the lower margin acute,forming a sharp keel. In somespecimens seen this keel was slowly reduceduntil it merged smoothlywith the palatal surfacein front. In others the anterior margin was obtuselydeclivous. The obtuseanterior cutting angle projectedbelow the marginsof the tomia for nearly a millimeter in a few individuals,and in these occasionalspecimens the resem- blancewas striking to thosebills of Quiscalusin which the ridgewas most poorly developed. Juvenile specimensof Megaquiscalusm. macrourusfrom Fort Clark, Texas, that had been collected just after they had left the nest, had the palatal ridge already well indicated though only about one-half developed. In the slender- billed forms known as Megaquiscalustenuirostris and M. nicara- guensisthe palatal keel was much as in M. major though slighter and lesspronounced. In Blackbirds belongingto the West Indian group knownas Holoquiscalusa raised line was also more or less developed. In general the growth was similar to that in Megaquiscalusas the posteriorportion was broad and rounded,while anteriorlythe ridge was narrowedand the lowermargin becameacute. There is some variation in the size of this anterior portion; in a few the crest is obtuselydeclivous in front, approachingthe conditionfound in Quiscalus,but neverwith the keelproduced so that it projectsbelow the plane subtendedby the cutting edgesof the tomia. The discoveryof a peculiarknoblike process on the palateof the mexicanorioles belonging to the specieslcterus gularis was oneof the really surprisingdiscoveries made duringa moreor lesscursory examinationof the palate in variousspecies and generaof Icte•idae pickedout at random,and it was the findingof this structurein an Oriole that led to a detailed examination of all of the material available. In Icterusgularis the palatal ridge is from 1.2 to 1.5 millimetershigh at its anteriorend (Fig. 2). The entirestructure is broad and somewhatflattened. The ventral surfaceis slightly Vol. 1OlOXXXVI1 J WETMORE,ThePalate in Icterido•. 195 rounded,the sidesslightly sloping, the sidesand lowersurface join- ing at a sharpangle. ]n front the ridgeis abruptlytruncated at its ventral marginwhere there is sometimesa slight tooth or proice-

Fig. 2. Head of Ivterus gularis yucataneusis. b. Palatal knob (about natural size.) tion. Below this point the anteriorsurface slopes abruptly, and then passesover into the roof of the palate. The ridgeis about two millimetersbroad, and there is a slightlyindicated raised line on the ventral surfacefor three-quartersof its length behind. From this descriptionit may be seen that this blunt projection is entirely differentfrom the sharplykeeled ridge found in Qulscalus. Examination of other orioles showsthat Icterus gularis stands alonein respectto this developmentas there is nothingfound in other speciesthat approachesit save for a broad, low, rounded projection,slight but distinct,that is foandon the palatein Icterus xanthornus. In Icteruslaudabilis and I. prostheraelasthere is a very slightlyraised median r/dge developed on the posteriorpart of the roof of the mouth. in twenty-eightother speciesbelonging to this genusthe palateexhibits no peculiaritiesworthy of mention. This structurein the bill in Icterusgularis is constantin its presence,and servesas a trenchantcharacter distinguishing it from other orioles, or in fact from any other membersof the Ictericla•that have been available for examination. The differencespointed out above, togetherwith othersof lesserimportance, seem to be of generic value. It is thereforeproposed to recognizefor this speciesthe genus name 196 ThePalate in Icteri&*. [April[ Auk

AndriopsarCassin. • Type.-- Ps[arocolius]gularis Waglet, Isis, 1829,p. 754 (typelocal- ity, Tehuantepec,Oaxaca). Diaono,i*.--Medium-sizedIcteridaz with short, heavy bill; a prominentknob-like projectionon the posteriormedian por6on of the palate,broad and somewhatflattened in generalform, with abrupt sides,truncated in •ront, sometimeswith a tooth or notch at the anterior ventral angle, about 2 millimetersbroad and •rom 1.2 to 1.5 millimetershigh in front; depthof eulmenat basenearly equalto one-halflength of eulmen(varying from slightlymore to slightlyless); tarsus slightly longer than eulmen from base; middle toe with claw equal to two-thirds,or slightly more, of length of tarsus. One speciesin whichthree subspecies have beendescribed is at presentknown to belongin this genus. Thesewill standas follows: Andrlopsargularis gularis (Wagler) And•opsar gularis tamaulipensis(Ridgway) zlndr•opsargularis yucatanensis(Berlepsch) At presentthere is no informationon the feedinghabits of these oriolesavailable but it seemscertain that they will showsome strikingpeculiarity in choiceof food or in mannerof securingand handlingit when the life historyof •he speciesis betterknown. In conclusionI desireto give a brief summaryof the condition of the palate in other Ictericlazwhere commentis necessary. In Euphaguscarohnus and E. cyanocephalusthere is a slight elongate ridge of low elevation,rounded posteriorly more acute in front, and not projectingas far as the level of the tomia. This raised line is slightlymore pronouncedin E. catolinusthan in E. cyano- cep•alv* in spite of the fact that the latter has a heavier,stronger bill. Thespeeies known as Pt2loxena atroviolacea hasan el?gate, narrow,slightly elevated ridge on the posteriorportion of the palate, rounded behind and more or less acute in front, but with too low an elevationto be considereda highlyspecialized structure. Sumi- ehrast'sBlackbird (Dives dives) has a palatalstructure somewhat resemblingthat of the genusHoloquiscalu* save that the entire ridge is shorter.

• Proc. Acad. Nat. Sci. Philadelphia, Vol. XIX, 1867. p. 49. Vol. 1919XXXVI] J WETMORE,The Palate in Icteridee. 197

With regard to others, Tangaviusa•eus has a slight ridge, that becomesstronger behind, extending for two-thirds the length of the palate. A similar ridge in Molothrusbadius is lessdeveloped at its anterior end than in the precedinggenus. ]n Molothrus fringillarius (one specimenonly examined)this ridge is still less in development. ln. Molothrusater, the cuttingedges of the tomia donot extendbelow the level of thepalate, and there is a rounded swellingbehind the center;in Molothrusatronitens only a very slightridge is present, and finallyin M. rufo-axillaristhere is no peculiarityworthy of mention. Nesopsarnigerrlmus shows a well marked roundedridge on the posteriorpart of the palate that mergesinto the anterior surfacewithout becomingproduced as an angle. Xanthopsarimthurmi shows a slightlydeveloped posterior ridge,while in Agelaiusphzeniceus (including gubernator) there is a very faint swellingat the posteriorend of the palate,that becomes much more pronouncedin A. tricolor. Agelaius thilius and A. ic•erocephalusshow a faintly raisedmedian line, that in the latter speciesis broadenedand rounded posteriorly. Amblyrhamphus holosericeushas a long,low, keeledmedian ridge, and in the three speciesof Sturnellathere is an elongatekeel, that is roundedbehind and •cute in front. in Curazusaterrimus the palate is on a level with the edgeof the tomia,and has a lowrounded bulge on its posteriorsurface. Trupialis militaris 'and T. falklandicushave a slight roundedposterior ridge, that is absentin T. bellicosaand T. defillipi,and finally.in Gymnomys•ax melanicterus there is a low, narrow,keeled ridge on the posteriorpart of the palate,that merges graduallyinto the surroundinglevel in front.• Noneof the other speciesseen present any marked peculiarities.