222 Unexplored Spain 
does the parent vulture incubate, that she allows herself to be 
completely buried on her nest beneath the drifting snow. On 
these hanging steeps the eyries are overlooked from above, 
yet not a vestige of the sitting vulture can be seen until she is 
disturbed by a blow from an axe on the trunk, or by a shot fired 
—then off she goes, dislodging a cloud of snow from her three- 
yard wings as she launches into space. 
BLACK VULTURE (Vultur monachus) 
The black vulture lays but one huge egg, often boldly marked 
and suffused with dark-brown and rusty blotches and splashes, in 
contrast with the eggs of the griffon vulture, which are usually 
colourless or, at most, but faintly shaded. 
The latter, so abundant in Andalucia, is remarkably scarce in 
Grédos, where we saw rather more eagles than vultures. The chief 
bird-forms of the high sierra were ravens and choughs, ring- 
ouzels, rock-thrush and black-chat (Dromolaea leucura). The 
alpine accentor (Accentor collaris) and alpine pipit (Anthus 
