6 NORTHERN SOCIABLE VULTURE. 
The nidification of the Northern Sociable Vulture, is thus described 
by the Rev. Canon Tristram, "Ibis," vol. i., page 282: — 
"This bird did not often come under my observation, but is a con- 
stant resident in the Sahara, though in very limited numbers. While 
the Griffon breeds throughout the Atlas, the Nubian seems to resort 
to more southern ranges for his eyrie. There is a breeding place to 
the south west of Biskra, in some lofty isolated cliffs, and another near 
the stupendous gorge of El Kantara, where I have watched these birds 
with the telescope. The heavier build, larger size, and short, stout 
neck and head, render this bird distinguishable at a glance from the 
Griffon, the plumage also appeared to me to be darker; but I am in- 
clined to think that the hues of all Vultures change much according 
to age. I noted three or four among the precipitous ridges between 
the Nizab country and the Oasis of Waregla, in lat. 32° N., and I was 
told by the natives that they remained there all the year. As we saw 
them in December, it is probable they breed in these cliffs. Their 
habits seem precisely similar to those of the Griffon." 
There is an egg of this Vulture figured in the " Proceedings of the 
Zoological Society for 1853," having a white ground, but thickly marked 
with irregular blotches of various shades of brown, especially towards 
the larger end. 
Mr. Gurney, from whose little treatise on Raptorial Birds I make 
the above quotation, informs me that he has two eggs in his possession, 
sent to him by the late E. Verreaux, as those of V. milieus; both are 
entirely white. One of them, stated to have been taken in Greece, I 
have figured. The bird is taken from one of the specimens in the 
Norwich Museum, kindly drawn for me by Mr. Reeve. 
