164 Birds of Colorado 
feeder and a scavenger, and in the south is a most valuable 
aid to sanitation. When a carcass is found, the Buzzards 
assemble and gorge themselves to repletion ; they retire 
to a perch close by to roost and digest, and return again 
and again until the bones are picked quite clean. 
When in the air they sail and circle high with out- 
spread wings, on the look-out for a meal. They have 
no note or cry beyond a hissing, wheezy sound. 
Buzzards, though not usually gregarious, often use 
a common roosting-place—Rockwell describes such a 
roost in a grove of trees on Plateau Creek, where he 
has seen as many as fifty of these birds assembled at 
night time. Morrison found them breeding in the La 
Plata mountains at an elevation of about 12,000 feet. 
The nest was merely a ledge in the cleft of a broken 
boulder on the mountain side; there were two eggs of 
a dirty-white colour, blotched with reddish-brown, 
these measured 2°73 x 1:95 and 2°70 x 1°91 respectively. 
The eggs were much soiled and the whole surroundings 
of the spot loathsome and evil-smelling. Dennis Gale 
is the other observer who has found the Buzzard breeding 
in Colorado. He reports that he saw several nesting 
in cotton-wood trees on the Little Thompson, with Blue 
Herons. They were probably making use of the nests 
of the Herons, though Gale, in his notes, does not dis- 
tinctly say so. This was on April 16th. 
Family FALCONIDZ. 
Head and neck never naked (in the New World forms) ; 
bill generally stout, strong and hooked, with a cere or 
soft cushion at the base within which the nostrils open ; 
nostrils never pervious ; wings with ten primaries, tail 
of twelve rectrices with rare exceptions; feet strong, 
toes cleft or only webbed at the extreme base, the 
