88 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



in dried skins they appear closely similar. The following may be of 

 aid in separating the two species: 



a/ Head (in life) mainly yellow; general coloration more uniform, blacker, 

 sheen of feathers of dorsal surface with green predominating, purple 

 restricted or nearly absent; wing coverts black without distinct paler 

 edgings C. urubitinga. 



a'. Head (in life) mainly red; general coloration less dark, more variegated 

 with brownish edgings to feathers, sheen of feathers of dorsal surface 

 with purple predominating, green restricted or nearly absent ; wing 

 coverts distinctly margined with brownish, this color often exten- 

 sive C. aura. 



The color of the shafts in the outer primaries is not of definite 

 value, as it is variable in both species. It has been alleged that in 

 urubitinga the feathering on the back of the neck extended farther 

 forward. This, however, is merely an age character, as immature 

 birds of either species have the neck more or less feathered to the 

 base of the cranium or even onto the nape, while in adults this area is 

 naked.''° 



That aura and urubitinga are distinct species there can be no doubt. 

 Though aura has a much greater zonal range, in tropical and sub- 

 tropical regions, aura and urubitinga are found together throughout 

 extensive areas, while they are sufficiently distinct to controvert any 

 theory that might consider them color phases of one species. 



The specimen from Las Palmas has the following measurements: 

 Wing, 514; tail, 217 (culmen defective) ; tarsus, 60; middle toe with 

 claw, 76 mm. These dimensions are somewhat larger than those of 

 birds from eastern Brazil, British Guiana, and Venezuela, so that it 

 is possible that a race characterized by slightly greater size inhabits 

 the basin of the Rio Paraguay. 



CATHARTES AURA RUFICOLLIS Spix 



Cathartes ruflcolUs Spix, Avium Spec. Nov. Brasiliam, vol. 1, 1824, p. 2. 

 (Interior of Bahia and Piauhy.) 



The geographical forms of the turkey vulture and the nomencla- 

 ture applied to them have been involved in much confusion and un- 

 certainty, a state that has not been remedied by the recent action of 

 Chubb '^^ in adopting ruficoUis as the proper name for the j^ellow- 

 headed vulture. A review of the entire group has shown that there 

 are apparently five forms of aura that may be recognized, two from 

 North America and the West Indies and three from South America. 

 In general it may be said that turkey vultures from North America 

 and the West Indies differ from those of South America in browner 

 coloration and more distinct brown edgings on the wing coverts. 



«» See Bangs and Penard, Bull. Mus. Comp. Zool., vol. 62, April, 1918, p. 34. 

 61 Birds of British Guiana, vol. 1, 1916, p. 211. 



