There is a light and a dark morph, although dark birds make up a small proportion of the population. The light plumaged birds have a whitish head and breast and reddish-brown thighs. The upperparts are a mixture of blacks and browns with rufous highlights. The unbanded tail is mostly white with shades of gray. Legs are feathered to the toes.
Dark birds vary, but are mostly dark with light-colored flight feathers.
Sexes are similar with females being larger. Black-tailed jackrabbits, ground squirrels and prairie dogs are some of the preferred items. Their wide gape makes them uniquely suited for swallowing larger mammals than other buteos. Some birds, reptiles and insects are also taken. The pair may return to its territory year after year, and they usually have several alternate nest sites.