470 Field Museum of Natural History — Zoology, Vol. IX. 



Adult, light phase: Upper parts, bright rufous brown, mixed with 

 dark brown, the centers of the feathers being the latter color; crown 



Ferruginous Rough-legged Hawk. 



and upper back mixed with more or less white; primaries, dark slaty 

 brown, the basal portion of the inner webs, white; under parts, white 

 or buffy white, sometimes almost unmarked but usually showing 

 streaks of rufous brown on the breast; belly heavily barred with 

 dark brown and rufous; thighs, deep rufous brown, barred with black 

 or dark brown ; tail, ashy white below, above pale ashy, shading into 

 white at the base and tip, and more or less edged with rufous brown. 



Adult, dark phase: General plumage, dark brown; wings and tail 

 similar in marking to the light phase but darker. 



Immature: Upper parts, dark brown, mixed with tawny and buff; 

 under parts, white, streaked and spotted with dark brown; tail, 

 without bars, the color variable, the greater portion, usually ash gray 

 becoming white at the base. 



Male: Length, about 22; wing, 16.50; tail, 9.20; tarsus, 2.70. 



Female: Length, about 23; wing, 16.75 to 17.75; tail, 9.50; 

 tarsus, 2.90. 



