They often congregate in open country near abun-dant sources of small rodents. This hawk is regularly seen hovering over marshes or prairies until it plunges down-ward to capture its prey. This habit is necessary because its choice of habitat often lacks high perches. They will use fence posts and telephone poles when available. Description Rough-legged Hawks are rather large hawks with plumages that can vary from light to dark, as well as vary with age and sex.
Some birds have light chests and dark bellies, while in others the pattern is reversed.
In dark birds, the entire body may be a dark chocolate brown or nearly black with a pale base to the outer primaries and tail. Immatures usually show a pale area at the base to the upper side of their tails in the lighter phases and a pale or white area above and below on the tails of dark-phase birds. Even the downy chicks can vary from nearly all white to a dark gray. The hawk is usually silent away from the nesting grounds, where its call may sound like high-pressure steam escaping or a catlike whistle.