Ferruginous Hawk
Buteo regalis
Glendale, Maricopa Co., Arizona, USA. 5 January 2013.
From Wikipedia: Adults have long broad wings and a broad gray, rusty, or white tail. The legs are feathered to the talons, like the rough-legged hawk. There are two color forms: Light morph birds are rusty brown on the upper parts and pale on the head, neck, and underparts with rust on the legs and some rust marking on the underwing. The upper wings are grey. The "ferruginous" name refers to the rusty color of the light-morph birds. Dark-morph birds are dark brown on both upperparts and underparts with light areas on the upper and lower wings.