197 
a summer inhabitant of the far north, passing through settled Canada only 
on migration. Both species are dichromatic and occur in light and dark 
phases with intermediate plumages. 
347. Rough-legged Hawk (Including American Rough- legged Hawk). Arch - 
ibuteo lagopus. L, 22. One of the largest of our Hawks, slightly smaller than the Fer- 
ruginous Rough-leg and comparing in size very closely with the Red-tailed. It occurs in 
a light and a dark phase, and has intermediate plumages. The commonest coloration (Figure 
217), the light phase, probably a juvenile plumage, is brown above, with much blended 
cream, or rusty ochre feather edgings that become more extensive on head. The base 
of the tail is cream, changing to dark for final half. Below — cream or dull light ochre, 
with practically solid and complete dark brown abdominal band, usually sharply defined 
at upper line. Face, foreneck, and breast more or less striped with brown. The dark phase 
is sohd, near-black like the corresponding plumage of the other Buzzard Hawks (See dark 
plumage, Plate XXVI B). Intermediate plumages have a peculiar speckled appearance 
of mixed brown or black, without systematic pattern. The only constant character of 
this plumage is the lightening or whitening of the basal half of the tail. 
Figure 217 
American Rough-legged Hawk; scale, fa. 
Appearance in flight of most characteristic plumage. 
Distinctions. With its feathered tarsus (like Figure 219), to be confused only with 
the Ferruginous Rough-leg. In the dark phases the two are absolutely alike in colour, but 
this species never has the large amount of pure white that the ordinary plumage of that 
species shows. In the pale phase the ochraceous breast and head and the conspicuous dark 
abdominal band (Figure 217) are distinctive. In the intermediate plumages, the Ferrug- 
inous never seems to have the irregular spotted or speckled mixture of this species. In 
the complete dark phase, the bill shape that is distinctive in any plumage is probably the 
best criterion. In this species, looking at the bill from above, it is narrow and constricted 
towards the gape (Figure 218) instead of being broad and “frog-mouthed” (Figure 221). 
Field Marks. Recognizable by its outline and high soaring 
habits as a Buzzard. 
Except in characteristic plumage with extensive dull ochre 
breast and sharply defined dark abdominal patch, it is difficult 
to separate it from several similarly appearing hawks. The under 
surface of the wing usually has a much more pronounced 
“thumb-mark” of dark near base of primaries than other com- 
parable species, and the tail, white at base and dark at end, 
shows a much wider, broader, and more pronounced tail band 
than in any other similar bird (Figure 217). The American 
Rough-leg has the same light spot at the base of the primaries 
on the upper surface of the wing, as the Ferruginous (Figure 
220 ). 
Nesting. On the ground, on rocky ledges, or in trees. 
Distribution. Northern parts of Northern Hemisphere. 
America nesting on the barren grounds across the continent. 
Narrow bill of American 
Rough-legged Hawk 
(from above V; 
natural size. 
A bird of the far north. In 
Wintering from Oregon and 
