Winter ecology, and specifically winter movements, are a little understood aspect of ferruginous hawk ecology throughout the west. Returns from juvenile ferruginous hawks banded over several years in southern Alberta showed these birds moved throughout the central plains to winter as far south as Mexico. More recent banding studies in Idaho have focused on whether the ferruginous hawks west of the Rocky Mountains interact with populations in the central plains during winter. Many of these hawks feed on black-tailed prairie dogs (Cynomys ludovicianus), a species being reviewed for possible listing by the US Fish and Wildlife Service. In Washington, it has been recognized for years that ferruginous hawks are not found in the state from September through February, but their whereabouts are unknown. It is important to understand not only where these threatened birds go for six months of the year, but also to identify their winter habitats and prey. These may be limiting population numbers by affecting individual survival and breeding health. Distribution of prey and winter habitats may also influence sporadic breeding tendencies and nomadism.

Satellite telemetry is providing new information on the winter whereabouts and ecology of Washington. s ferruginous hawks. In spring, 1999, we captured ten of these raptors on nesting territories near the Tri-Cities in Benton and Franklin counties. The hawks were instrumented with Platform Terrestrial Transmitter Terminals (PTTs), otherwise known as satellite transmitters. The miniature transmitters send UHF signals to passing NOAA satellites which retransmit the hawk. s locations back to ground stations. Within a couple hours of transmitting, the location coordinates of the hawk, accurate to within 150 m, can be downloaded via computer. The technology has been used successfully by WDFW researchers since 1993 to study the movements of nesting and wintering bald eagles. Over the next several months we hope for the same success in unlocking the mysteries of ferruginous hawk movements.