thumb|The tail is white with a dark terminal band.

thumb|The legs, but not the toes, are feathered.

The rough-legged buzzard (Europe) or rough-legged hawk (North America) (Buteo lagopus) is a medium-large bird of prey. It is found in arctic and subarctic regions of North America, Europe, and Asia during the breeding season, and migrates south for the winter.

Four subspecies of Buteo lagopus are accepted: In northwest Russia, rough-legged buzzards may feed on small rodents in the years when rodent density is high, and shift to alternative prey (ptarmigans and hares) in the years when small rodents are scarce. The rough-legged buzzard will also supplement its diet with mice, rats, gerbils, pikas, shrews, squirrels of the genera Spermophilus and Tamias, and insects. Like most Buteo species, rough-legged buzzards have been reported both still-hunting (watching for prey from a perch and then stooping) and watching for prey while in flight. Unlike most other large raptors, they may engage in hovering flight above the ground while searching for prey. In autumn, Rough-legged buzzards leave their breeding grounds in late September and migrate southward to their wintering areas. This movement is primarily driven by the inaccessibility of small rodents in the Arctic during winter due to continuous snow cover and polar night, during which they are unable to hunt. By late April, they return to their breeding sites.

Their migration follows a distinctive "foxtrot" pattern, characterized by alternating quick and slow phases.

Nests are built soon after arrival to breeding grounds and require 3–4 weeks to complete. Twigs, sedges, and old feathers are used as building materials. Nests are in diameter and in height.

Longevity and mortality

Rough-legged buzzards that survive to adulthood can live to an age of 19 years in the wild; however, perhaps a majority of individuals in the wild do not survive past their first two years of life. The threats faced by young rough-legs can include starvation when prey is not numerous, freezing when Northern conditions are particularly harsh during brooding, destruction by humans, and predation by various animals. The chances of survival increase incrementally both when they reach the fledging stage and when they can start hunting for themselves. Death of flying immatures and adults are often the result of human activity, including collisions with power lines, buildings, and vehicles, incidental ingestion of poison or lead from prey, or illegal hunting and trapping. Other reasons for nestling mortality are earth-slides of the river-banks, where rough-legged buzzards often build their nests, and chilling.

Vocalization

Adult rough-legged buzzards will give alarm calls when intruders approach a nesting site. It is described as a downward slurring whistle, sounding like kiu wiyuk or a lengthy descending kee-eer similar to that of the red-tailed hawk. This cry is given in flight or from a perch every 15–30 seconds. During courtship, both sexes have been recorded to give a whistling sound that changes to a hiss. Following copulation, females will give a cluck-like sound and males give a whistling noise. Fledglings will give begging calls while waiting for parents to provide food.

  • Rough-legged hawk – Buteo lagopus – USGS Patuxent Bird Identification InfoCenter
  • Rough-legged hawk Species Account – Cornell Lab of Ornithology
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