l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



average of 8) ; tarsus 68.5-75.1 (70.7) ; approximate width of central 

 rectrix 59-70 (63.4) mm. 



Females (3 specimens), wing 510-512 (511, average of 2) ; tail 

 272-285 (279), culmen from cere 23.9-25.5 (24.6), tarsus 69.3-72.5 

 (70.9) ; approximate width of central rectrix 60-67 (64.3) mm. 



Type, male, wing 508, tail 272, culmen from cere 26.2, tarsus 68.5, 

 approximate width of central rectrix 63 mm. 



A color photograph of a recently killed adult male, taken by John P. 

 O'Neill at Tingo Maria, Peru, July 1, 1962, shows clearly that the 

 iris was red ; bill flesh color ; side of the head and throat deep yellow 

 to light orange ; and the crown and a spot in front of the eye deep blue. 



Range. — From southeastern Colombia (Rio Vaupes), the Rio 

 Orinoco in southern and eastern Venezuela (Isla Corocoro, Ama- 

 zonas; Piacoa, Delta Amacuro), British Guiana (Kartabo; Rock- 

 stone; Kamakuna), and Surinam (Keiserberg Airstrip; Wilhelmina 

 Mountains), to eastern Peru (Rio Curanja, Loreto; Tingo Maria, 

 Huanuco) and central Para in northern Brazil (Tauary on the Rio 

 Tapajos; Tapara on the Rio Xingu). 



Remarks. — As my studies of specimens of the yellow-headed vul- 

 tures progressed it became evident that there were occasional speci- 

 mens that did not agree with the usual pattern of Cathartes hurro- 

 vianus in size and color. In fact, certain birds were definitely trouble- 

 some in attempts to outline characters under which this species could 

 be recognized. The first of these aberrant individuals was a skin in 

 the American Museum of Natural History, an adult female of un- 

 known locality that had died in captivity at the New York Zoological 

 Society zoo on December 23, 1918. Presently I saw another of similar 

 form in the Museum of Comparative Zoology, and later others in the 

 Chicago Natural History Museum. At first I supposed that these 

 might be the bird described briefly by Sharpe (1874, p. 26) as Oenops 

 pernigra, but in due course when I saw this type it proved to be an 

 individual of Cathartes aura ruficollis. There remained the possi- 

 bility then that they were Cathartes urubitinga, named by Pelzeln 

 from northern Brazil, but when I visited the Naturhistorisches 

 Museum in Vienna I found that the type series were all individuals 

 with duller color of hurrovianus, and with the size of the southern 

 population of that species listed above under Pelzeln's name as 

 Cathartes hurrovianus urubitinga. It became obvious then that the 

 larger birds represented a distinct group that has been overlooked. 

 Since their known range is included within that of C. b. urubitinga 

 they must be regarded as a distinct species. 



