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Rough-legged Hawk Revisited

By Marcy Mahr

Like me, you may have had to sit down with a field guide on more than one occasion to sort out the various hawk species that inhabit our area. Particularly challenging is distinguishing the subtle differences in plumages, which are confusingly similar. Birding field guides read, “plumage is extremely variable,… both dark and light forms are common, … in the light morph look for,… with many birds intermediate between the extremes, …in intermediate immatures also note… .” And relative size is not always easy to judge; on days of poor lighting, I have often puzzled over: is it a Sharp-shinned or a Cooper’s Hawk?

When the cool fall weather moves into the Flathead, most of our nesting hawks move southward. So long, most of you Northern Harriers and Sharpshinned! Safe travels, Swainson’s, and Ferruginous Hawks! See you next spring, Osprey! And welcome back, Rough-legged Hawk! Rough-legs come down from their breeding areas in the far north to over-winter in the Flathead Valley. No tropical winter vacation for these hardy birds. Even on the most blustery days, they are the sentinels on our fence posts. They hover as they hunt in our fields, as if fixing themselves to an invisible sky hook and suspending time.

When I asked Dan Casey about what raptors he and other observers had seen during this fall’s raptor migration at Jewel Basin, Dan said, “As we wound down the count for the season, it was clear that this is a good site for a number of birds, most notably accipiters, which comprised 50% of the season’s totals.” Dan noted that Rough-legs, which are typically rather unusual at inland hawk watch sites, had been rather uncommon in the Flathead until around the last week of October, although the first one passed the hawk watch site on September 25th. “We had immature, adult females and adult males. Our season total of Rough-legs ended up at 41, with 22 of those sighted on Sunday, October 26th.” This makes Rough-legged Hawks the 7th most common of the 17 raptor species Dan and his crew counted this fall. (Please refer to Dan’s article for more information on the Jewel Basin Hawk Watch.)

The Rough-legged Hawk is quite variable, with light and dark morphs, and differences between male, female, and immature plumages. Despite its wide variety of plumages, Rough-legs are typically brown above and paler below, with a dark belly and a pale head. Their broad, dark, subterminal tail band and black wrist patches are diagnostic, and the long white tail with dark band or bands helps to identify this hawk in all plumages. Adult males typically have multi-banded tails with broad blackish subterminal band. Adult females’ tails are brown toward the tip with a thin black subterminal band, and immatures show a single broad brown tail band. Wings are broad and long, spanning about 52-54 inches. Seen in flight from above, the white at the base of the tail is conspicuous. Viewed from below, look for dark wrist patches, and legs feathered to the toes.

Did you know the Rough-legged Hawk, the Ferruginous Hawk, and the Golden Eagle are the only American hawks to have legs feathered all the way to the toes? In fact the name “Rough-legged” Hawk refers to this feature. Hence its scientific name, meaning “hare-footed”, reflecting this hawk’s adaptation to its arctic home range. Just imagine being Erik Pontoppidan, a Danish author, bishop, historian and birder back in 1763 who first described the Rough-legged Hawk. Whereas most hawks migrated further south for the winter, Pontoppidan encountered a hawk with feathery legs that flew down from the northernmost parts of Europe and remained in Denmark for the winter.

Rough-legged hawks are a good reminder of our connectedness to places far from the Flathead, and also that our valley can be a pretty good place to spend the winter. Rough-legged Hawks are back!

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