44 



BULLETIN 15 3, UNITED STATES NATIONAL MUSEUM 



individual variation they exhibit. It therefore seems best not to 

 attempt to " split " the species into races. 



Recently W. P. Lowe ''^ has put on record some field observations 

 of the plumage variations and changes of this and other vultures. 

 He writes in conclusion that it may be stated definitely that sehil- 

 lingsi, fiillehorni, and zechi are synonymous, " * * * merely 

 based on age and sex, of one species, Pseudogyps africanus.'''' Ac- 

 cording to this writer, the first plumage is dark brownish, the head 

 and neck well covered with brow^nish down; the neck pale bluish- 

 gray with some yellow spots. " * * * After probably four or 

 five years, still dark brown. Down of neck greatly diminished, head 

 and neck black. Breeds in this plumage." The next stage is simi- 

 lar to the last, but the back is white, spotted with brown. Finally, 

 " * * * adult males very dark, almost black, including crop- 

 patch. Adult females very pale dirty drab. Very old birds, whit- 

 ish. Crop-patch brown. Ruff pure white in both sexes." 



Mearns took the following measurements of seven birds in the 

 field. 



He wrote at the time that — 



* * * from the resemblunce in size and form I am satisfied tliat these 

 seven are conspecific. The neck is long and slender, the skull narrow, nostril 

 vertical, or parallel to side of base of culmen. Skin of head and neck is slaty 

 black, like the bill and cere ; head apparently covered with fine hairs, thickest 

 on top of the head, dirty .white in color ; neck more or less covered with tufts 

 of whitish down, quite heavy on the nape; chest patch furry, sooty brown. 

 Feet and claws slaty black. Iris, in all seven, very dark brown. The adults 

 have white rumps and backs, two of them have this white faintly tinged with 

 clay color, perhaps dirty. The immature birds rejiresent a different plumage, 

 dark below, under wing-coverts dark, rump and back dark, neck ruff darker, 

 with feathers narrower and centrally streaked -with whitish like the sides and 

 underparts. I suppose the white-backed birds to be adult, the dark-backed, 

 immature. Using " adult " to indicate white-backed, and " immature " to 

 indicate dark-backed birds, I will describe the plumage of the seven fresh birds. 

 All have the soft parts colored alike, except that the long, nearly naked necks 



'ojbis, 1929, pp. 439-442. 



