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Rough-Legged Hawks

Dear Bird Folks,

I’m wondering if you can help me identify a hawk my wife and I saw last week. We were walking near Corn Hill in Truro when we saw this large hawk hovering over a field. The hawk was hanging still in the air, staying in one spot like a hummingbird might do. Suddenly the bird dropped to the ground and captured something. Then, instead of flying off to a nearby perch to eat it, the hawk went back to hovering, just like it did before, only now it was holding the small creature in its talons. Then, while still hovering, it reached down, grabbed the creature from its feet and swallowed it whole, without ever landing. Do you know what kind of hawk would have such an unusual hunting behavior?

-Tom, Truro, MA


Nice job Tom,

Too many people try to identify birds based on their coloration alone. All day long folks inquire about mystery birds by saying things like, “It had a brown tail.” When I ask the person if the bird was scratching on the ground like a sparrow, or picking at the tree trunk like a woodpecker or snagging insects off the tips of branches like a warbler, they reply, “It had a brown tail.” Behavior and overall impressions are very important to bird identification. In fact, Pete Dune, the mega birding star from Cape May, NJ, has written a book on bird identification and there is not a single illustration in the entire 700 page book. Pete describes each North American species, one at a time, and teaches us how identify birds without having to rely on pictures. Actually, there is one picture in the book, it’s a photo of Pete. No bird book would be complete without Pete’s smiling face. He wants to make sure Hollywood knows what he looks like when they call.

Based upon your excellent description, Tom, I’m guessing the bird you saw was a Rough-legged Hawk. Quite often Roughed-legged Hawks hover when they are hunting. Other hawks, including the ubiquitous Red-tail, occasionally hover too, but I’m getting tired of writing about Red-tails, so I’ve decided your hawk was a Rough-leg. Now before you accuse me of drawing conclusions based upon my own writing needs, another observation you made also suggests a rough-leg. You said the hawk scooped up the prey and ate it while still hovering. I seem to remember reading someplace that rough-legs occasionally eat prey while on the wing. So, based on your description and my foggy memory, the evidence points to a Rough-legged Hawk.

The Rough-legged Hawk is a large hawk. It’s a bit bigger than our pal the red-tail, but not nearly as common, especially in these parts. It breeds way up in the Arctic tundra and only travels south during the winter. The bird’s name “rough-legged” refers its feather-covered legs and is not implying that it needs a new leg razor.

Most of us have seen large hawks sitting in a tree along the interstate, looking for something to pounce on. Trees and posts are important to many hawks, but where rough-legs breed there are no trees. To compensate they have adapted the ability to hover. If the wind is blowing hard enough they can hang in one spot for quite a while. It makes sense that the bird you saw at Corn Hill was able to hover. I can’t remember a time when the wind wasn’t blowing on Corn Hill. Never go up there before a big date, Tom, your hair will be a mess for days.

Up north, on the breeding grounds, the rough-leg’s main food source are the plump and juicy lemmings. Like the Snowy Owl, rough-legs reproduce best during years when the lemming populations are high. But in years when the lemming population crashes there are few new rough-legs raised and some adults may not even breed at all. In the late summer the hawks leave the high Arctic and head towards the good old USA, where they switch from eating lemmings to mice and voles. They must change their diet because we don’t have any lemmings down here, if you don’t count the ones who listen to Bill O’Reilly.

Winter is the best time to look for Rough-legged Hawks and the best places to look for them are in wide open fields, marshlands or dunes. It is quite unlikely that a rough-leg will be found in the deep woods or in your backyard, unless you are lucky enough to have a yard that is crawling with lemmings.

You were fortunate to see the Rough-legged Hawk hovering, because it can be rather tricky to identify them based on their plumage alone. Their coloring is extremely variable. These hawks come in assorted shades of brown, including light brown, dark brown, medium brown and brown-brown. If you hadn’t notice it hovering you may have been one of those people who stubbornly repeatedly to me “It had a brown tail.” Don’t worry, Tom, I wouldn’t have made fun of you, at least not until you walked away.