Ferruginous Rough-leg 179 
tawny wash, often the black massed across the abdomen. Young birds 
are very similar, but have the basal half of the tail white, the terminal 
portion dusky brown with a white tip, while below the brown is chiefly 
massed across the belly. In the melanistic phase both young and old 
are entirely deep black, except for the white forehead, the white on the 
inner webs of the quills above the notch, and some broken bands on the 
tail. The two phases are connected by every gradation of intermediate 
states. Iris brown or yellow, bill bluish-horn, cere and legs yellow, 
claws black. Length (of a male) 21; wing 17-5; culmen 1-2; tarsus 
27. The female is larger—wing 18-0. 
Distribution.—Breeding in the northern North America, from Alaska 
and Yukon to the lower St. Lawrence Valley ; south in winter over 
the greater part of the United States as far south as Virginia and 
southern California. 
In Colorado the Rough-legged Hawk is not uncomon on the eastern 
plains, and perhaps in the foothills from November to March, but it has 
been but little noticed, and definite records are wanting. I have not 
heard of it on the western slopes. There are several examples in the 
Aiken collection from El Paso co., one an adult male taken January 
15th; and Henshaw also states that he saw several near Colorado 
Springs in November. Warren informs me that Mr. Hersey shot one 
near Orchard as late as March 26th. 
Habits—The Rough-legged Hawk is a peaceful and 
unoffending bird, which preys chiefly on meadow mice 
or voles of the Arvicoline group in its winter range, and 
on lemmings in the far north. As the voles are highly 
destructive to crops and to fruit trees, especially in 
winter, this Hawk is undoubtedly a most valuable aid 
to the farmer, and should be most rigidly protected. 
It is somwehat crepuscular in its habits, and obtains 
its prey either by watching from a fixed point or beating 
to and fro, like the Harrier or Marsh-Hawk, over the 
meadows with slow and noiseless flight. 
Ferruginous Rough-leg. Archibuteo ferrugineus. 
A.O.U. Checklist no 348—Colorado Records—Ridgway 73, p. 186; 
Henshaw 75, p. 425; Allen & Brewster 83, p. 197; Drew 85, p. 17; 
Dille 85, p. 44; 87, p. 97; 03, p. 74; Morrison 89, p. 8; Kellogg 90, 
p- 90; Bendire 92, p. 259; Lowe 97, p. 69; Cooke 97, pp. 75, 204; 
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