Monthly variation in home range of a steppe-dwelling raptor

Birds in steppe landscapes change their behaviour over the annual cycle. We used GPS telemetry to track 12 steppe-dwelling adult Ferruginous Hawks (Buteo regalis) to understand how their home ranges varied across the year. Home range sizes of territorial adult hawks showed strong intra-annual variation, being smallest from April to June, and largest from July to October. Patterns in home range size were likely linked to intrinsic factors such as the timing of breeding and migratory behaviour, and to extrinsic factors such as prey availability associated with specific landcover types. These results have implications for our understanding of the response of steppe birds to predicted changes in land cover, and they suggest potential relationships between human activity and wildlife behaviour. Because the birds we tracked used a large portion of western North America, they are likely relevant far beyond the small area where these individuals were trapped.