398 CLAR•:,Black-wfn•ed Palm Tanafter. LOct.•-Auk

THE BLACK-WINGED PALM .

BY AUSTIN H. CLARK.

THROUGHthe kindnessof Mr. Outram Bangs, I have been enabledto examinethe large seriesof 2•anagrapalmarummelan- optera(Sclater) in his collection,as well as thosein the collection of the Museumof ComparativeZo51ogy at Cambridge. The localities represented in the series, with the number of specimensfrom each, are as follows: Panama, x9; Santa Marta, x; Margarita Island, 3; Trinidad, 2; "Venezuela," x; Yacura, Venezuela, x; Lake Titicaca, Peru, 2. In addition to these examples,I have,in my tabulation,made use of the measurements givenby Mr. Ridgway• for skinsfrom the followinglocalities: Costa Rica, 6; Panama, 2; Trinidad, 2; British Guiana, i; Lower Amazons, 5; Rio Huallaga (Peru), 2. This brings the whole number under discussionup to forty-seven. For comparison, specimensof •. palmarum palmarum, were studiedfrom Santatern0), Bahia (x), and "" (3). The object in view was to observethe variations of this sub- specieswith regard to its geographicaldistribution, and to deter- mine whether the northern , occurring about Panama, is separableas a valid form, which Ridgwayconsiders may prove to be the case. Dr. Sclater• gives the distribution of fanagra palmarum as "southern Brazil and Bolivia northward to Trinidad, Venezuela, Colombia, Panama, and Costa Rica." The subspeciesmelanop- tera is given3 as occurringin the western part of South America, from south to eastern Peru (type locality), and east to Trinidad, including Colombia, Ecuador, Venezuela, and the Amazons valley. This restricts T. palmarum palmarum to east- em and southeasternBrazil, north to British Guiana. Ridgway says that in the samelocality in the lower Amazons district, examplesoccur, representing as to coloration,at least,both forms;

Birds of North and Middle America, Part II, p. 59. Catalogaeof the in the British Museam,Vol. XI, p. •6o. Ridgway,loc. cit. Vol.x9o3XX'] -I CLARK,Black-wln•ed ]•alm Tana•,er. 399

while Sclater statesthat in Guiana (Demerara and the Mt. Ror- aima region), Surinam (Dutch Guiana), and on the island of Mexicana (Lower Amazons), intermediategrades occur, the olive-greenedgings to the wing feathersin thesespecimens being only slightly manifest. In the absence of material from these localities,I cannotmake any remarkson this point, but I merely wishto call attentionto the fact that, while Sclaterregards melan- opleraas a good subspeciesof 2"na•ra palmarum, Ridgway is inclinedto considerthem as entitledto full specificrank. In the accompanyingtable are given the averagesfor all the male specimensfrom the variouspoints. •'romthe figures it willbe seen at oncethat, as regards the wing, the largestspecimens are from Peru, while the smallestare from Panama; starting at Panama,the averagerises west into Costa Rica, and east, through Santa Marta, Yacura, and Margarita Island, to Trinidad. The lower Amazonsspecimens are the same size as those from Costa Rica, and are smaller than those from Guiana and Trinidad.

l•11gASURIgMIgNTSOF Tana•ra •alrnarum melano•tera SCL.

Ratio of Localities Tail Wing Culmen Tarsus Wing and tail

Peru 98.8 76.9 •.28 •3'5 21 '4 Panama 90.8 68.2 • .36 •3.2 2o .6 Costa Rica 94.2 •.32 •3 20.8 SantaMarta (•i Col})mbia 93 72 1.29 20 Yacura, Venezuela 94 73 •4 20 Margarita Island 96 .3 •4 20 6 ß "Venezuela" (•) IOO •'37 •3 20 Trinidad 97.2 70.8 x'37 •4 21 British Guiana 97'5 72.9 •'33 •3 20.6 Lower Amazons 94'7 71.4 • .32 •3.2 2o.8

Tana•ra •almarum •almarum Max.

Brazil 99 72.2 •.37 •4.5 22.2

The tail measurements,ho•vever, do not vary in the salneway. Although the birds with the shortesttails are from Panama, those 4OO CL.XRK,Black-wt'nvc•ed PalmTanafter. [AukLOct. with the next shortestcome from Trinidad, while Margaritan birds have the longestof any, with the. exceptionof Peruvian examples. Costa Rican birds are close to those from the lower Amazons. By dividinglength of wing by length of tail, we obtaina ratio betweenthe two. An examinationof these figures showsthat Peruvianbirds have the longesttails proportionately,while those from Trinidad have.the shortest. Specimensfrom middle north- ern Venezuela(Santa Marta, Yacura,and Margarita) and from Costa Rica are intermediate. Those from Panama resemble most closelyTrinidad examples,while the lowerAmazonian form agrees with the Costa Rican. In regard to the lengthof the chord of the cuhnen,birds from Yacura, Margarita, and Trinidad exceed all others. Guianan and Costa Rican specimensagree in having very short beaks,while those from Peru, Panama, and the lower Amazons are intermediate. Tarsal measurements show that Costa Rican and lower Ama- zonian birds are identical in this character; while Trinidad and Peruvianbirds are prettyclose, having the longesttarsi. Panama specimenshave shortertarsi, agreeingwith those from Guiana; Santa Marta and ¾acura ones have the least of all, while the Margaritan form is intermediate between them and the bird of Trinidad. In measurementsthe true • palmarum palmarum from south- easternBrazil is larger than the averageof the subspeciesmelan- opteraexamined in respectto length of wing, culmen,and tarsus; but in tail measurements it is near the Santa Martan bird. The ratio betweenlength of wing and length of tail is that of Trini- dadian melanoptera. In short, then, the specimensof • palmarum meIanaptarafrom CostaRica show a striking similarity in all dimensionsto those from the lower Amazons. Peruvian birds are largest, exceptfor the beak, while Trinidad birds are near them in all respectssave in length of tail. Guiananbirds are also close, having longer tails than those from Trinidad. There seems to be a regular gradationfroin Panama along the coast to Trinidad. The most strikingfact is the sinall size of the Panamabirds as compared with those froin Costa Rica on the west and Santa Marta and ¾acura on the east. Vol.x9o3XX-] C•x• Black-win•edPalm Tana•cr. 4_0I

There seems to be no constant variation in color; but this character is uncertain in these birds, and differences are to be met with in specimensfrom the same locality. The violet gloss is the most noticeablefeature. This glossis, however,mainly confinedto the distal portion of the feather, and seemsto undergo considerable diminution, often a month before the feathers are renewed again. Even in fresh specimensfrom the same place the difference is considerable,some, apparently adult, having ahnostnone, while othershave it very stronglymarked. From the data just given, it appearsthat, as would be expected, the largest specimencome from the high mountainsof Peru. Here doubtless food is comparatively scarce, and a bird must cover a considerablearea in order to obtain a sufficientsupply. Size,therefore, is a distinctadvantage. The lowerAmazons sup- ports a small race. Food here is abundant, and so natural selec- tion is not called upon so urgently to weed out the smaller and weaker individuals. The race is small at Panama for the same reason; while mountainousCosta Rica, Santa Marta, Yacura, and Margarita are inhabitedby larger birds. .Very likely the birds on Trinidad are stragglersfrom the rough and barren Venezuelan shore, where the small ones have been eliminated. The seriesexamined contains two interestingspeci•nens. One has a peculiarlylong and narrow bill, but is otherwiseapparently normal. This bird, a male, was taken on Margarita Island, and 5vasnoticed in ' The Auk ' for July, •9o2, p. 266. The other is a partial albino. It is a young malex, and was taken at Loma del Leon, Panama,on March 3, •9 oo. The left wing has the proximal secondaryattenuated, short, and with its b.xsaland central portionswhite. The next secondaryis normal; but the third has a large white distal patch, extendinginwards •$ mm. from the tip of the feather. The patch is central in posi- tion, and does not reach the border on either side. From the appearance of both these feathers the conditionmay be patho- logical. The Black-wingedPahn Tanager is very commonon the island of Trinidad, where it can be seen at ahnost any time about the

Collectionof E. A. and O. Bangs,No. 7467. 402 $•o.•Rass,GeosjbLza , Cocornt• and Certhld[a. L[' Oct.Auk gardens in Port-of-Spain. It is very active and restless. The song of this bird is unlike that of any of ours, being a quick ascendingsuccession of notes, pitched very high. There is a suggestionof pantingand of effortin the song,and its high key, which makesit somewhatsqueaky, is rather disagreeable.

NOTES ON THE ANATOMY OF G•EOSPIZ•t, COCOR2VIS, AND CœR THIDI•t.

BY ROBERT E. SNODGRASS.

, Plates XVJJ-XX.

Geos,•izaand Certhidiaare the two distinctivelypeculiar avian genera of the GalapagosIslands. The former consistsof a large numberof speciesand varieties,and has alwaysbeen regardedas belonging to the family Fringillidm. Ce•'l,Sidia,consisting of eight varieties comprised in two species,was formerly placed in the Ccerebid•e,but both Lucas and Ridgway now regard it as belongingto the Mniotiltid•e. Cocornisis known only from the small island of Cocos,lying off the Gulf of Panama and northeast of the GalapagosIslands about four degreesnorth of the equator. It consistsof one knownspecies, and has alwaysbeen assignedto the Fringillidm. But it has probablybeen so classified•nore on account of its general resemblance to Geos.piza than frorn a con- sideration of its 'own characters. In all structural points Cocornisreally resemblesd2'rl•5idia more than it resembles Geos.piza. To be sure, the adult males of Cocorn/sand of most of the Geo.•iz• speciesare almost plain black, while the adults of Cer#zidia are gray with admixturesof olive and brownish. Yet, in the shapeof the bill and in the struc- ture of the skull Cerlhitlia and Cocor;•is are almost identical. On the other hand, the structural differences between Cocornisand Geos.Piza are slight--the slender-billed Geos.pizre differ from Cocornisin the characters of the skull and skeleton of the bill,