48 BIRDS OF LA PLATA 
that grey country. The English colonists on the 
Chupat, Durnford says, call it the ‘‘ White Horse,” 
owing to its conspicuous white colour often deceiving 
them when they are out searching for strayed horses 
in the hills. It is a wary bird, and when approached 
has the habit of rising up in widening circles to a 
vast height in the air. When sailing about in quest 
of prey it usually maintains a height of fifty or sixty 
yards above the surface. The stomachs of all the 
individuals I have examined contained nothing but 
the remains of cavies (Cavia australis). 
The nest is built on the top of a thorn bush, and is 
a large structure of sticks, lined with grass, fur, dry 
dung, and other materials. The eggs are greyish 
white in colour, blotched and marked, principally 
towards the large end, with two shades of umber- 
brown. 
GREY EAGLE 
Geranoaétus melanoleucus 
Above black, wings grey with narrow transverse black bars; tail 
black ; throat grey ; breast black with round whitish spots ; abdomen 
white ; bill horn-colour, feet yellow ; length 26, wing 19 inches. 
THE Grey or Chilian Eagle, like most diurnal birds of 
prey, undergoes many changes of colour, the plumage 
at different periods having its brown, black, and grey 
stages: in the old birds it is a uniform clear grey, 
and the under surface white. Throughout the 
