The Northern Harrier (Circus hudsonius) has a distinct facial disk. It breeds from Alaska and N Canada to Baja California and S USA. Winters to extreme N South America and West Indies. Widely spread in Old World.
53cm (21”), 450g. ♂: head and upperparts light gray; below White, dotted with cinnamon; tail gray, barred with brown. Bill blackish with bluish base; iris, cere and legs yellow. ♀: Superciliaries, throat and cheek-patch white; head, neck and underparts streaked with buff and dark brown; tail light brown barred with blackish. Iris brownish; cere pale greenish; legs pale yellow. Young: like female but below rufous with little streaking; white areas of face and rump tinged with buff.