Laura Erickson's For the Birds

This splendid raptor breeds on the tundra, specializing on lemmings—hamster-sized rodents. It is one of only three American raptors with leg feathers extending all the way down to the toes, which explains its name. (The other two are the Golden Eagle and Ferruginous Hawk.). Nonbreeding adults eat about a quarter-pound of food daily (about a tenth of their body mass), which amounts to about 5 small mammals. Nestlings start feeding themselves (swallowing lemmings whole) at about 16 days old. It’s estimated that a brood of 2 nestlings requires 26 pounds of food during the 40 days between hatching to fledging.

In winter, Rough-legged Hawks descend to open areas in Canada and the Lower-48. Some years there can be dozens in Minnesota’s Sax-Zim Bog; other years they can be few and far between here.

Rough-legged Hawks hunt more in areas experimentally treated with vole urine (visible in ultraviolet light) than in control areas. The hawks probably associate the urine with rodent-rich spots.