178 Birds of Colorado 
instance was noticed by A. S. Bennett at Lay in Routt 
co., July 10th, 1889 (Fisher). In this case they were 
engaged in feeding on locusts. 
The nest, according to Gale, is generally placed in a 
cotton-wood, tree, about twenty-five to fifty feet above 
the ground. It is made of twigs and lined with a little 
grass or strips of pine bark. The eggs, usually three 
according to Gale, two according to Bendire, are faintly 
greenish, and are as a rule very lightly spotted and 
marked with reddish-brown. They average 2°25 x 1:7, 
The old nest is generally occupied year after year. Gale 
found fresh eggs from May 15th to 30th. Dille gives 
June 5th. 
Genus ARCHIBUTEO. 
Very similar to Buteo, but with the tarsus feathered to the base 
of the toes ; usually four outer primaries emarginate on the inner web ; 
melanism very common. 
A small section of the Buzzards, with representatives in the northern 
parts of the Old and New Worlds; two species in the United States. 
Key or THE SPECIES. 
A. Bill smaller and weaker, chord of the culmen and cere about 1.2; 
belly with a patch of black in the normal phase. 
A. 1. sancti-johannis, p. 178. 
B. Bill stouter and stronger, chord of the culmen and cere about 
1.6. thighs rufous with black cross-bands in normal phase. 
A. ferrugineus, p. 179. 
American Rough-legged Hawk. 
Archibuteo lagopus sancti-johannis. 
A.O.U. Checklist no 347a—Colorado Records—Ridgway 73, p. 186; 
Henshaw 75, p. 425 ; Drew 85, p. 17; Morrison 89, p. 8; Nash 96, p. 15; 
Cooke 97, p. 75. 
Description. Plumage very variable—in the normal light phase, 
mingled white, dusky brown and black above, white prevailing on the 
head, the upper tail-coverts and the inner webs of the primaries above 
the notch ; tail chiefly white, with two or three transverse black bands 
and a white tip; below mottled white and dusky, sometimes with a 
