Rough Legged Hawk Guide (Buteo lagopus)

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Joe was first inspired by birds at the age of 6, watching the Barn Swallows nesting in his garden shed. He worked as an ornithological consultant. After a decade of migration research and seabird conservation, he now works as an ornithologist guide on expedition cruise ships. He drives small boat tours, leads hikes ashore, and gives presentations on board.

Taxonomy at a Glance

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitiridae
Genus: Buteo
Species: Buteo lagopus

How to Identify a Rough-legged Hawk

Rough-legged Hawks are not usually easily and immediately identifiable from other hawk species, but with good close views and experience, separation should not be too difficult. While they can be rather variable in their plumage, particularly those in North America, certain plumage features and structural differences are consistent and noticeable. Most birds are the typical ‘‘light morph’’ but ‘‘dark morphs’’ do occur, most frequently in birds close to the Pacific and in northeast Canada.

The most striking and reliable identification feature is that all Rough-legged Hawks have a mostly white tail with a dark band at the tip. Adult males have at least one additional narrower dark band before the broad terminal band. Dark morph birds may have a fairly dark uppertail, but this basic pattern should be visible on the undertail.

Rough-legged Hawk adult male underside — An adult male Rough-legged Hawk, showing the distinctive white tail with dark terminal bars. Photo by Joe Cockram, in winter in Colorado

Light morphs are overall quite pale on the underside, with distinct black wing tips and a black trailing edge to the wing. They also show a blackish carpal patch (the wrist, on the bend of the leading edge). These dark areas contrast with a creamy white base color with variable brown barring, which is densest on the underwing coverts.

The underside of the body is also creamy white, usually with heavy dark barring, which merges to form a large black-brown belly patch on adult females and some males. As the name suggests, Rough-legged Hawks have feathered legs, with only the yellow feet being visible bare skin.

The head is also variably cream or brown, sometimes with dense, thick streaks. The bill is quite small, with a yellow cere (the fleshy bill base around the nostrils). The back and upperwing are brown, with some pale streaking on the back and upperwing coverts and indistinct darker barring on the flight feathers.

Juveniles are similar to adults, but the dark tail tip, wing tip, and trailing edge on the underwing are not so distinct. The underwing coverts and head are light buff with brown streaking, and they have a solid brown belly patch. In flight from above, a pale patch is visible towards the outerwing, but the actual wing tip is dark. The white tail with a dark band at the tip is still the most important identification feature at this age.

With experience and familiarity of other more common species, Rough-legged Hawks can also be separated by their structure and flight action when plumage details are not apparent, in a bad light, or at a distance. Compared to other hawks, Rough-legs are a little longer winged and longer tailed, creating a subtly different silhouette. When soaring, they hold their wings up slightly and bent at the wrist. They frequently hover when hunting, much more so than other hawks.

The most similar and most common confusion species are the Red-tailed Hawk in North America and the Common Buzzard in Eurasia. These are likely to be more abundant throughout the winter range of Rough-legged Hawks and often in the same habitats. Compared to both of these, Rough-legged Hawks also have a smaller bill and feathered legs, as well as the features mentioned above.

Where Do Rough-Legged Hawks Live: Habitat

Rough-legged Hawks have a very distinct breeding range, restricted almost entirely to tundra and, less frequently, in taiga habitats, in subarctic and arctic North America, Europe, and Siberia. They prefer open, treeless, or sparsely wooded country, both inland and coastal. Within this, they are comfortable in fairly flat areas, such as river valleys, bogs, and coastal plains, and also in uplands and mountainous regions.

In winter, they migrate south to more temperate zones throughout most of the United States (except the south-east) and south Canada. They are more numerous in northern states. Many go to The Great Plains and the broad agricultural valleys in the west. Northern European breeders move to central and eastern Europe and, less commonly, the United Kingdom.

Siberian breeding birds migrate to the vast steppes and plains of central Asia and the coasts of Far East Asia. While it is more difficult to avoid human habitation in winter, they tend to be found again in the most remote and open country where small mammal prey is abundant, usually farmland, grassland, and marshes.

Like most raptors, Rough-legged Hawks are not a willing over-water migrant, and their migration routes are focused over land, not crossing oceans and avoiding large waterbodies wherever possible. I have seen them struggling to complete a 30 mile crossing of Lake Eerie from Canada to the USA in the fall, a journey that countless small passerines undertake with absolute ease.

buteo lagopus distribution — Blue — wintering area
Green — nesting area

Rough-Legged Hawk Diet and Feeding

Rough-legged Hawks feed mostly on small mammal prey. On breeding grounds in the Arctic, lemmings and voles are the most frequently hunted species, but this varies depending on seasonal fluctuations in prey populations.

Lemmings are notorious for their ‘‘boom or bust’’ population cycles, and their abundance will have a big impact on Rough-legged Hawk breeding success in any given year. They will also take other rodents, including mice, rats, and shrews, during both breeding and wintering seasons.

Small birds are also hunted, though a limited variety of species occurs in the tundra breeding areas. Favored avian prey includes passerines like Lapland Longspurs, Snow Buntings, and American Tree Sparrows, also larger birds like shorebirds, waterfowl, Ptarmigans, and young geese. Lacking the speed and agility of falcons and smaller hawks, birds are a difficult prey item, and so the less mobile nestlings and fledglings are preferred.

In more temperate and developed/agricultural wintering areas, a greater selection of prey is likely to be available, including rabbits and a larger variety of open country birds. Like many raptors, they will also happily scavenge whatever protein opportunities they encounter and will take advantage of road kill and other carrion, mass insect hatches, and I have even seen them taking earthworms from recently cultivated fields in winter.

Rough-Legged Hawk Breeding and Nesting

Rough-legged hawks reach sexual maturity at around two years of age and arrive in breeding areas after spring migration in late April to late May. Courtship has not been well studied but usually mostly consists of simultaneous soaring and calling by both partners. ‘‘Sky dancing’’ appears to be performed less frequently than it is by other hawks, possibly due to the paucity of food available in the early season and the necessity of conserving energy.

The nesting site is chosen to provide a comprehensive view of the surrounding area, often on a cliff or crag, sometimes high in trees. Both the male and female construct the nest, with the male doing most of the material collection and the female completing the assembly after his delivery. Sticks and twigs make up the majority of the construction, and the nest is lined with grasses and sedges and hair and feathers found nearby.

3-5 pale green-white, finely streaked eggs are laid, maybe more (up to 7) in a year when lemming prey is highly abundant, or conversely, fewer eggs in a poor lemming year. Incubation is performed almost entirely by the female for roughly one month. The male will keep the eggs warm when the female is feeding on prey that he has brought to her to consume away from the nest.

After hatching, the female again looks after the chicks at the nest. The male will bring food for her and the chicks, and he might help with feeding them. After 40 days, the young are capable of flight, and they will stay dependent on their parents for another month before dispersing and making their own way south for the winter.

rough-legged buzzard — Photo by Tom Koerner

Rough-Legged Hawk Population

The remoteness of the Rough-legged Hawk breeding range and fluctuating nature of breeding success make it very difficult to accurately measure their population. The global population is estimated at 500,000 individuals, making them one of the more abundant species of raptor, largely due to the extensive range the species is found over.

Are Rough-legged Hawks Endangered?

As a species that nests entirely in high latitudes in boreal forests and arctic tundra, where human activity is low, Rough-legged Hawks do not appear to be threatened and are classed as ‘‘Least Concern’’ by IUCN. They do encounter human pressures on their more southerly breeding grounds, though apparently not causing issues at the population level.

Previously persecuted by farmers, this has been reduced by legislation, and much winter mortality is now accidental in the form of collision with wires and road vehicles and electrocution on power pylons.

Rough-Legged Hawk Habits

Rough-legged Hawks are solitary birds. In summer, they associate only with their partner and, of course, the chicks once they hatch. In winter, they hunt alone but sometimes do come together in small loose flocks to roost overnight.

While many similar sized and closely related raptors rely on wooded habitats for hunting or at least the presence of regular trees and high perches from which to survey the terrain for prey, Rough-legged hawks have a hunting technique that allows them to utilize much more open country.

Repeated hovering gives them the height required to locate small mammals moving in thick vegetation directly below before retracting their wings and dropping onto their target. This ability reduces competition with more abundant congeners that they would otherwise be frequently coming into contact with in winter and allows them to breed in the vast, open expanse of the arctic tundra, where suitable perches are in short supply.

It is possible that they can even see the ultraviolet reflections from vole urine, indicating areas of high prey activity in which to focus their hunting efforts.

Rough-Legged Hawk Predators

As a sizeable raptor themselves, adult Rough-legged Hawks are not regularly hunted by any species. On their breeding grounds, they may be taken opportunistically by other, larger raptors, including Golden Eagles, and potentially by Gyr Falcons.

Eggs and chicks in the nest, however do face threats, particularly from mammalian predators, notably Brown Bears, Arctic Foxes, and Wolverines. Some birds will also target nesting sites, with Common Raven, Snowy Owl, and jaegers being the most frequent and likely nest-robbers. In wintering areas, roosting Rough-legged Hawks are a viable prey item for large night-hunting owls; Great Horned Owl in North America and Eurasian Eagle Owl in Europe and Asia.

golden eagle — Golden Eagle, the one whom rough-legged hawk should avoid

Rough-Legged Hawk Lifespan

The oldest recorded wild Rough-legged Hawk reached 18 years of age, and they could live to well over 20 years old in captivity. Many Rough-legged Hawks will die before reaching one or two years old, with starvation being a major cause of mortality. This is a particular threat soon after gaining independence from their parents. Finding and successfully hunting prey is difficult for young birds, especially in years when prey abundance is low, and even experienced adults struggle to find enough to eat.

FAQ

Question: Do Rough-legged Hawks have rough legs?

Answer: The name refers to the fact that Rough-legged Hawks have feathered legs, only the feet are bare. This is an adaptation to the cold climate where they live, further north than most other raptors. The feathers help to insulate the legs, otherwise heat would be lost from the bare skin. Other raptors have bare legs as the cold weather is less likely to be a problem, and the feathers could get sullied while eating their prey.

Question: Do any other birds have ‘‘rough legs’’?

Answer: Yes, a few other birds have feathered legs like the Rough-legged Hawk. Other raptors such as Ferruginous Hawk and Golden Eagle, which can both experience cold winds in the plains and mountains where they nest. Ptarmigans, a grouse living high in mountains, including through the winter, have feathered legs and even have feathered feet to ensure they stay insulated.

Question: How can I see a Rough-legged Hawk?

Answer: Only the few people visiting the high arctic are likely to see Rough-legged Hawks in their breeding areas, and even then they are spread out sparsely over vast areas. You are most likely to encounter them on migration and in their wintering quarters. Raptor migration watch points are often the best places to see them.
These locations are located in positions where large numbers of raptors are funneled past obstacles to their migration, such as between mountain ranges, or at the narrowest crossing of a water body, sometimes hundreds can be seen in a day. In winter they inhabit much more accessible locations, the best way to locate one is to drive around open farmland, scanning fence lines for one perched on a fence post, or looking for their distinctive hovering technique while they hunt.

Conclusion

Rough-legged Hawks are enigmatic birds, filled with the character of the high Arctic. To survive and indeed thrive as they do in such a hostile and apparently barren environment is an impressive example of the adaptability and resolve of nature. It is truly a special moment for a birdwatcher if one graces our local birding patches during the winter months.

Research Citations

Ferguson-Lees, J.; Christie, D. (2001). Raptors of the World. London: Christopher Helm. ISBN 0-7136-8026-1.
Bechard, M. J., T. R. Swem, J. Orta, P. F. D. Boesman, E. F. J. Garcia, and J. S. Marks (2020). Rough-legged Hawk (Buteo lagopus), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.
del Hoyo, J.; Elliot, A.; Sargatal, eds. (1996). Handbook of the Birds of the World. Vol. 3. Barcelona: Lynx Edicions. ISBN 84-87334-20-2.
BirdLife International (2022) Species factsheet: Buteo lagopus

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