Rough-legged Hawk (Buteo lagopus)

The lemmings in the sub-arctic and arctic regions of Canada and Alaska must of had a bumper year in 2021 because the mid-west United States had an irruption 2021/2022 winter season for the Rough-legged Hawk (RLHA). Lemmings are the primary food source for this beautiful species during its summer nesting cycle. Typically, during our winters, RLHA are found in ones or twos in Missouri, south to the Missouri River. Around the St. Louis area we may only see one or two birds in a typical winter. This season was quite exceptional. Looking at the occurrences for this past season documented in eBird shows this species has been seen across the state, up and down the Mississippi River, even as far south as the Arkansas border. On a birding day in February, Miguel, Dave and I counted eight as we moved along the Hwy 79 corridor.

On an early mid-February morning Miguel and I hit one of our favorite winter birding locations in St. Charles County to see what luck we could have. We knew a RLHA or two had been reported and photographed by multiple folks and we had our hopes high. Nothing much was showing up on this frigid morning but I thought to check a specific area that was off the beaten path and had a history of holding birds that wanted to get away from the busy roads and throngs of gawkers. That is when we ran into an individual RLHA of our dreams. We wound up spending hours with this cooperative bird despite freezing fingers, toes and tips of our noses. We simply stood outside our vehicles and watched as the bird perched, hover-hunted, soared and fed, all the while seeming oblivious to our presence. The following video and images are the results of this day.

Rough-legged Hawk, February, St. Charles County, MO
The entire population of RLHA migrate for the winter. The light-colored iris of this bird suggests it is a juvenile. Juveniles are very difficult to discern the sex of, but juvenile males are more likely to travel further south during their migration.

The three images above show the bird hover-hunting. This process can be seen in the video as well. The RLHA will hunt by the more typical buteo standard of sitting on a perch and waiting for the right opportunity to show itself. However, because they spend roughly half of their lives in or around the tundra biome where there are few trees or other tall perches to do so, they have developed this method of hunting that allows them to stay high above their prey. They will often start very high, using their keen eyesight to spot the motion of a rodent. They will then descend in tier-like steps, getting closer to their eventual target until finally making their catch. It is quite a sight to watch a buteo of this size hover-hunting and something I doubt I could ever get tired of watching. I think these images show some modifications that help them in hover-hunting. Their wings are longer and narrower than most buteos and their tails are longer and broader as well. With these tools they can keep their heads nearly completely stationary in the sky for minutes at a time.

Right after the catch. This is the poor mouse that was eaten in the video. During winter, hawks of this size may eat 4-8 rodents a day.
The distinctive feathered legs can be easily seen in this image. This namesake trait is referred to in not only the common name, but in the specific epithet as well – lagopus referring to “hares foot”. This trait, found only in the Rough-legged Hawk, the Ferruginous Hawk and the Golden Eagle in North America, is undoubtably an adaptation for survival in the cold environments that these birds inhabit.
Rough-legged Hawks come in a dark phase coloration as well. This bird was photographed in Lincoln County, MO this year.
This is a different juvenile that was photographed in Lincoln County, MO this season.

How I would love to see them in their nesting range some day! These birds typically nest on rocky cliffs and because there is often a lack of sticks and branches available in the tundra, they will often use caribou bones to build their nests. They line their nests with soft vegetation like moss and lichen as well as the fur and feathers of their prey.

Because they are so-well adapted to living on the wing, in more open and treeless areas, the RLHA will outcompete species like Red-tailed Hawk and Ferruginous Hawk that prefer to hunt from tall perches. If you have spent enough time in the field, you have probably watched Red-tailed Hawks attempting to hover-hunt when the winds are just right. However, they cannot keep this activity up for very long and do not do it nearly as well as RLHA.

Rough-legged Hawk taking off.

I hope this post gives a good glimpse into the winter life of the Rough-legged Hawk and why, when asked what is my favorite bird species, this is one out of ten or so that I would give as the answer.

-Ozark Bill

5 thoughts on “Rough-legged Hawk (Buteo lagopus)

  1. Thanks for sharing info. I have what i’m sure is a ridiculously silly question, but i’m curious. Why the abbreviation RLHA, and not just RLH?

  2. That’s a good question, Lori. Bird banders and ornithologists developed an official code to make their lives easier and now a lot of general birders and naturalists use it as well. There is good reason that this four-letter code is used and, in general, it does a good job at keeping things straight in North America. It has been modified by different groups but see here for the original publication to get an understanding of the rules for this naming convention.

    Click to access p0016-p0025.pdf

  3. Thank you Bill for this exceptional post – the narrative was so well written that gave the reader a wonderful picture of these magnificent raptors behavior and winter life. Not to mention the stunning images. Ev

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