Uploaded September 2025 | Updated September 2026, 2 weeks ago
The Rough-legged Hawk (Buteo lagopus) is a raptor that breeds in Arctic and high subarctic regions around the world, migrating to more southerly regions each year to delight intrepid winter birders. The name "Rough-legged" refers to this raptor’s fully feathered legs, a feature shared by the Ferruginous Hawk and Golden Eagle.
Besides its feathered legs, the Rough-legged Hawk also has a noticeably small beak. These features illustrate a biological principle known as Allen's Rule, which states that the appendages of endothermic (warm-blooded) animals in colder climates are relatively smaller than those in warmer climates. Smaller, feathered features minimize bare surface areas and help reduce heat loss, critical requirements for survival in freezing polar regions. Allen’s Rule can be seen in other Arctic-dwelling birds such as the Snowy Owl, Arctic Tern, and Willow Ptarmigan.
This handsome raptor is about the size of a Red-tailed Hawk, but its long, narrow wings appear more plank-like in flight. It has a habit of hovering as it hunts over open spaces, rather like an overgrown American Kestrel, and often perches on the tips of branches and shrubs, where similar-sized hawks rarely alight.
Also known as: Rough-legged Buzzard (Europe), Roughleg, Black Hawk, Mouse Hawk, Squalling Hawk, Aguililla Ártica (Spanish – Mexico)
The Rough-legged Hawk (Buteo lagopus) is a raptor that breeds in Arctic and high subarctic regions around the world, migrating to more southerly regions each year to delight intrepid winter birders. The name "Rough-legged" refers to this raptor’s fully feathered legs, a feature shared by the Ferruginous Hawk and Golden Eagle.
Besides its feathered legs, the Rough-legged Hawk also has a noticeably small beak. These features illustrate a biological principle known as Allen's Rule, which states that the appendages of endothermic (warm-blooded) animals in colder climates are relatively smaller than those in warmer climates. Smaller, feathered features minimize bare surface areas and help reduce heat loss, critical requirements for survival in freezing polar regions. Allen’s Rule can be seen in other Arctic-dwelling birds such as the Snowy Owl, Arctic Tern, and Willow Ptarmigan.
This handsome raptor is about the size of a Red-tailed Hawk, but its long, narrow wings appear more plank-like in flight. It has a habit of hovering as it hunts over open spaces, rather like an overgrown American Kestrel, and often perches on the tips of branches and shrubs, where similar-sized hawks rarely alight.
Also known as: Rough-legged Buzzard (Europe), Roughleg, Black Hawk, Mouse Hawk, Squalling Hawk, Aguililla Ártica (Spanish – Mexico)
