Birds of prey, also known as raptors, are a group of birds that primarily hunt and feed on small animals. There are many different species of raptors found across Canada, but when looking for those with white tails, one species stands out as the most likely answer: the rough-legged hawk.
Rough-legged hawks are medium-sized raptors that breed in the Arctic tundra and migrate south to Canada and parts of the United States for the winter. They can be identified by their large size, broad wings, and distinctive pattern of black and white plumage. When in flight, rough-legged hawks display a mostly white tail with a single black band, making them relatively easy to identify.
Rough-legged hawks hunt over open habitats like grasslands, marshes, and agricultural fields, where they feed primarily on small rodents like voles and lemmings. Their migration is timed to match the availability of these prey species. Due to declines in vole populations, rough-legged hawk numbers have dropped in many areas. They are now considered a species of conservation concern across their range.
Physical Description
Rough-legged hawks are one of the larger Buteo hawks, with adults reaching 18-26 inches in length and 39-59 inches in wingspan. Their relatively long, broad wings allow them to soar over open habitats while hunting. These hawks have a large head and thick, chunky body compared to other Buteos. There are two color morphs: light and dark. The light morph has a white head, breast, belly and tail with black wingtips, a dark belly band, brown upperparts and black wrist patches. The dark morph is almost entirely chocolate brown except for the banded tail.
Juveniles resemble adults but have a buffy wash over their plumage. Their tails have a wider subterminal band compared to adults. All ages have feathered legs that extend to their talons, unlike many other raptors. This likely helps insulate their feet in frigid Arctic environments.
Range and Habitat
Rough-legged hawks breed in Arctic and subarctic regions of Alaska, Canada, Scandinavia and Russia. They migrate south to winter in southern Canada and the northern United States. migration extends only as far south as southern Ontario and British Columbia in Canada. In the U.S., they reach from the Pacific Northwest through the Great Plains and Midwest to New England.
This is a highly migratory species that travels thousands of miles between its breeding and wintering grounds every year. The migration south from the Arctic starts in late August and September. The return trip occurs in March through May. During winter and on migration, rough-legged hawks frequent open habitats including grasslands, marshes, tundra, shrublands and agricultural areas.
Diet and Hunting
Rough-legged hawks feed mostly on small rodents like voles, lemmings, mice and ground squirrels. They also eat some birds, insects, reptiles and amphibians. These hawks hunt while soaring or perching in a spot that overlooks open terrain. Once prey is spotted, the hawk will stall, hover and plunge down to grab its target in its talons.
Their huntingsuccess depends largely on the population cycles of lemmings and voles in the Arctic tundra. When prey is abundant, rough-legged hawks can raise as many as 5-7 young per nesting pair. In lean years, they may produce no young at all. Declines in southern vole populations are believed responsible for decreasing rough-leg numbers in migration and winter areas.
Breeding and Nesting
Rough-legged hawks return to the Arctic each spring to breed and nest. Courtship displays including aerial maneuvers and dramatic dives help pairs reestablish their bond. Nests are large stick platforms built on cliffs, bluffs, riverbanks, road cuts or utility towers. The female lays 3-5 eggs that hatch after about 32 days incubation. The young fledge the nest at 35-42 days old.
These hawks show a high degree of nest site fidelity, returning to the same area each year. However they rarely use the same nest twice, preferring to build a new one nearby. More than one pair may nest in close proximity on the same cliffside. Both parents help build the nest, incubate the eggs and deliver food to the young.
Conservation Status
The rough-legged hawk has a very large range and breeding population, but it faces a variety of threats on its breeding and wintering grounds. The use of pesticides in North America has reduced prey populations and contaminated some raptors. Loss of grasslands and wetlands in migration and winter areas has also caused declines. As a result, rough-legged hawk numbers today are believed to be declining across much of their range.
Partners in Flight estimates the global breeding population at 140,000 and rates the rough-leg as a Species of Regional Concern, though not a watchlist species. They are listed as Least Concern on the IUCN Red List. Ongoing monitoring, habitat protection, and management strategies will be needed to stabilize populations of this distinct Arctic raptor.
Key Facts
- Scientific Name: Buteo lagopus
- Length: 18-26 inches
- Wingspan: 39-59 inches
- Identification: Large, broad-winged hawk with feathered legs. Mostly white body with variable black accents. Broad black-banded white tail.
- Habitat: Arctic tundra, grasslands, marshes, agricultural areas
- Diet: Small rodents, some birds and insects
- Range: Breeds in Arctic, winters in Canada and northern U.S.
- Conservation Status: Species of Regional Concern
Conclusion
The rough-legged hawk is uniquely adapted to spend summers nesting in the extreme Arctic climate and winters hunting in more temperate areas of North America. Its distinctive black and white plumage and broad white tail with a terminal black band make it relatively easy to identify in flight. While still common and widespread, the rough-leg faces threats from pesticides, habitat loss, and climate change. More research and monitoring will help ensure this iconic raptor remains a part of the northern landscape for a long time to come.
