The behavior of the Ferruginous Hawk (Buteo regalis) has not been studied extensively during the non-nesting season. Ferruginous Hawks are less social than most other hawks of the genus Buteo. They are not known to flock in migration (Brown and Amadon, 1968, Eagles, Hawks and Falcons of the World, McGraw-Hill, New York) and are rarely found in groups in winter.
In the only previous report of a communal winter roost of this species, Steenhof (1984, Wilson Bull. 96:137–138) described a South Dakota roost in cottonwoods (Populus deltoides) being used by one to six Ferruginous Hawks on 11 of 25 mornings during the winter of 1975–76. On nine of the mornings, the roost was shared with Bald Eagles (Haliaeetus leucocephalus).