Rough-legged Hawk
| Scientific Name | Buteo lagopus |
| Survival Strategy | Medium-distance migrant to long-distance migrant |
| Return to the Midwest | November |
| Departure | March to April |
| Summer Range | Northern Canada (between 61°N and 76°N) |
| Conservation status | Least Concern |
Spring
Observations suggest that some rough-legged hawks arrive on their breeding grounds in May already in pairs formed during the winter, with nest-building beginning soon after. Typically, the female lays 3-5 eggs in May or June in a nest of twigs constructed on a rocky ledge or occasionally in a tall tree.
Summer
The female incubates eggs for 31 days, and brooding continues for three weeks after hatching. Young hawks will begin fledging at 40 days and often remain with their parents until they migrate south.
Fall
Rough-legged hawks leave the Arctic tundra in mid to late-September and arrive in the upper Midwest in November. Like snowy owls, they are an irruptive species whose numbers vary dramatically from year to year. They are often found perched in the middle of tall trees, on utility poles, or hovering above a grassy field.
Winter
As winter ends, rough-legged hawks begin their northward migration to their Arctic breeding grounds. Most hawks will depart by mid-March to early April.
Behavior
Hunting
Rough-legged Hawks are most active early in the morning and shortly before sunset. They have small beaks and talons that allow them to retain heat better due to the smaller surface area; however, this limits food choices to smaller mammals. They often hunt from a perch in a tree, preferably one that overlooks corn stubble and grasslands. They will also fly low over open fields in search of prey. After spotting a rodent, they will hover above their potential meal and then descend quickly, trapping it in their sharp talons.
Urine Trails
Rough-legged hawks can see the ultraviolet reflection of voles’ urine trails. They use urine trails to select productive hunting sites like a deer hunter uses deer trails. Fields with many trails will offer a better chance of a successful hunt.
Physiology
Staying Warm
Rough-legged hawks take their name from the feathers covering their legs, keeping this northern visitor warm. During cold weather, they “fluff” their feathers (piloerection), creating air spaces for insulation. They will also pull one leg into their feathers to reduce heat loss (unipedal resting). These feathers may also offer protection from the teeth of their rodent prey.
Diet
Rough-legged hawks feed on rodents and other small mammals. One adult rough-legged hawk needs to consume about 10% of its body mass each day. That equates to eating 4 to 6 small mammals (about a quarter-pound).
Lifespan and Mortality
The average life span of a rough-legged hawk is about two years.
Predators
Adult rough-legged hawks have few predators. Jaegers will take eggs while Arctic foxes, wolves, and snowy owls will prey on nestlings.
Cold spring weather, starvation due to a lack of prey, and nest predation make surviving the first months of life a challenge. Collisions with cars, powerlines, and radio towers are additional causes of mortality in adults.
Climate Vulnerability
Audubon’s computer modeling suggests an average temperature increase of 1.5ºC would likely result in a 36% reduction in the summer breeding range.
Never Stop Learning
Art: Robert Bateman painted Rough-legged Hawk in the Elm (1966) from a second-floor bathroom window of an old farmhouse.
First Nations: The Ojibwe word for hawk is “gekek.”
References
| 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. https://doi.org/10.2173/bow.rolhaw.01 |
| Rough-legged Hawk in the Elm by Robert Bateman http://robertbateman.ca/paintings/RoughleggedHawkintheElm.htm |
| Audubon Guide to North American Birds: Rough-legged Hawk https://www.audubon.org/field-guide/bird/rough-legged-hawk |
| Hawk Mountain Sanctuary: Rough-legged Hawk https://www.hawkmountain.org/raptors/rough-legged-hawk |
| How to ID a Rough-legged Hawk (video) https://youtu.be/PFzYncpwDbY |
| Ojibwe People’s Dictionary: Hawk https://ojibwe.lib.umn.edu/main-entry/gekek-na |