It breeds on cliffs, slopes or in trees, laying about four eggs, but more in good lemming years. It hunts over open land, eating mainly small mammals, and will come to carrion. This species, along with the Osprey, is one of the few large birds of prey to regularly hover.
This is a broad-winged raptor, typical of the genus. Compared to Common Buzzard, it is longer-winged and more eagle-like in appearance. It has feathered legs (hence its scientific name) as an adaptation to its arctic home range. It has small feet.
It has a wide variety of plumages, but is typically brown above and paler below, with dark belly and carpal patches. The head is typically pale. The tail is white with a dark terminal band. Some Canadian birds are all-dark, comprising up to 40% of the population in the east.