(Science: zoology) Any one of several species of large hawks of the genus Archibuteo, having the legs feathered to the toes.
Synonym: rough-legged hawk, and rough-legged buzzard.
The best known species is Archibuteo lagopus of northern Europe, with its darker American variety (Sancti-johannis). The latter is often nearly or quite black. The ferruginous roughleg (Archibuteo ferrugineus) inhabits western North America.