If there was a Guinness world record category for the fastest capture of a Rough-legged Hawk, we may have set it at Goose Pond on December 17, 2021.
Neil Paprocki, PhD student at the University of Idaho, is gathering data for a project called Differential Migration in North American Rough-legged Hawks (Buteo lagopus). Almost 150 Rough-legs have been outfitted with GPS backpack transmitters since 2014 to better understand their migration patterns. This generates an enormous amount of valuable data, but almost all of those birds were captured in the western United States. In an effort to expand the scope of the project, Neil is focusing on trapping Rough-legged Hawks last winter and this winter in the Great Plains, Midwest, northeast states, and southeastern Canada.
Seventeen Madison Audubon volunteers in 10 parties drove 342 miles and searched over 100 square miles for Rough-legged Hawks and all raptors in the open country Arlington-Empire Prairie area on December 12 in anticipation of Neil’s visit later that week. They found 3 Bald Eagles, 14 Northern Harriers, 1 Cooper’s Hawk, 50 Red-tailed Hawks, 7 Rough-legged Hawks, and 15 American Kestrels.
Rough-legged Hawk with dark wrists. Photo by Arlene Koziol
Rough-legs prefer to hunt in treeless habitats like tundra, marshes, prairie, and agricultural land. It’s easy to assume that a large raptor in the distance is a Red-tailed Hawk, but take a closer look. Rough-legged Hawks have narrower wings with dark carpal (wrist) patches on the underside, lack a red tail, and have pants (feathered legs) to help them survive in cold weather habitats. Plumage is variable. One dead giveaway is their tendency to stop and hover, kestrel-like, while searching for prey.
A Rough-legged Hawk preens at Goose Pond Sanctuary in January 2021. Imagery from the Goose Pond Webcam.
Neil and I started early on December 17. Forty-five mile per hour gusts scoured fields and drifted snow the day before making hunting on the wing nearly impossible, so we hoped the Rough-legs would be particularly active in the calm morning hours. The wind had subsided, but my relationship with birds and fish are similar. If I have a prediction about what they’ll do, they’ll more than likely do something else. I packed a lunch and thermos of coffee in preparation for a long day.
Our first location where two parties found a Rough-leg on December 12 was half a mile south of Goose Pond at the Arlington Agricultural Research Station. As soon as we entered university land, we saw a Rough-legged Hawk perched on a Kestrel box monitored by Madison Audubon volunteers. It was staring right back. We crept along slowly in Neil’s car without stopping to avoid the intense scrutiny of the hawk’s vision, its head constantly following the vehicle. Neil popped the door, and with a practiced flick of the wrist, landed the Bal-chatri trap on the shoulder of the road. We hardly had the car parked when she glided from the Kestrel box and attacked the trap. Bal-chatris are effective but there are no guarantees, and we waited for a tense moment to see what would happen. When it was clear the hawk was caught, we ran to the trap before she could work herself free, secured her in hand, and removed the three monofilament loops from her toes that had kept her grounded. I’ve assisted with raptor trapping before, but this capture within 10 minutes of searching was by far the fastest action I’ve seen!
We moved quickly and efficiently to minimize the hawk’s distress, and for the next hour we:
Fixed an aluminum band to her leg
Recorded morphometric (wing chord, mass, etc) data
Determined she was at least four years old
Attached the cell phone solar powered GPS backpack transmitter
Drew blood to study immunology
Checked for parasites
Swabbed her beak and talons to determine prey preference
Took photos for plumage color and wing area characteristics
Dorothy’s wing is held out on a grid to determine wing area. Photo by Neil Paprocki
Dorothy’s wing is held up with a color standard to document plumage color variation. Photo by Neil Paprocki
After double and triple checking her backpack, we released the Rough-legged Hawk, now with transmitter ID #215627 snugly attached. #215627 isn’t a very charismatic name. We decided to name her “Dorothy,” in celebration of Dorothy Haines’ 100th birthday on January 3, 2022. Dorothy (the human) has been an enthusiastic and curious volunteer, contributor, and close friend of Goose Pond Sanctuary and Madison Audubon since the 1970s. Dorothy was also instrumental in establishing the Wisconsin Wetland Association along with Jim and Libby Zimmerman. Happy Birthday Dorothy!
Dorothy Haines holds photos showing the Rough-legged Hawk named for her. Photo by Brenna Marsicek / Madison Audubon
GPS coordinates are recorded by the tracking device and transmitted to cell phone towers once every couple of days. Since Dorthy’s transmitter is solar powered, it has the potential to collect data for years. Between December 17 and January 4 she moved around an area of about 14 square miles and spent much of her time around Goose Pond or on the UW Arlington Agricultural Research Station. She was even spotted perching in a spindly cottonwood by the Goose Pond Webcam on December 21. While Rough-legs do prefer open country, Dorothy has been roosting almost exclusively in two farmyards, presumably in spruces (stars on map indicate roosting locations). Seeing how Dorothy utilizes Goose Pond Sanctuary and adjacent land is a great learning experience, but we’re excited to see where she nests this summer. Northwest Territories? around Hudson Bay? Baffin Island? Stay tuned.
A map of Dorothy’s movements since she was outfitted with a GPS unit.
Madison Audubon purchased the transmitter fixed to Dorothy to assist Neil in his research. We’ve got a special eye on her and five other birds of prey directly involved with Goose Pond including Arlene (Red-shouldered Hawk), Madison and Otto (Red-tailed Hawks), and Columbia and Fond Du Lac (Snowy Owls). Read our recent Friday Feathered Feature about them here. All wear similar backpack GPS transmitters, and they’re each providing a steady stream of information to inform future conservation. It’s a pleasure to work with these fierce and enigmatic creatures, along with the people who study them.
Thanks to Neil Paprocki for capturing Dorothy; to Sue Kaehler, with Cedar Grove Ornithological Station, for providing location data and interpretation; to the volunteers who surveyed for raptors, and for donors to Madison Audubon. For more information, visit the Rough-legged Hawk Project Facebook Page.
Written by Graham Steinhauer, Goose Pond Sanctuary land steward
Cover photo by Neil Paprocki
COOL FACTS AND RANGE MAP ARE BELOW FROM CORNELL
The name "Rough-legged" Hawk refers to the feathered legs. The Rough-legged Hawk, the Ferruginous Hawk, and the Golden Eagle are the only American raptors to have legs feathered all the way to the toes.
Nonbreeding adults eat about a quarter-pound of food daily, or a tenth of their body mass - that’s about 5 small mammals. Nestlings start feeding themselves (swallowing lemmings whole) at about 16 days old. It’s estimated that a brood of 2 nestlings requires 26 pounds of food during the 40 days between hatching to fledging.
The Rough-legged Hawk’s cliffside nest, a bulky mass of sticks, sometimes contains caribou bones. Nesting pairs need a lot of space: usually only a single pair will nest on a quarter-mile-long cliff. However, the pair may nest within 100 feet of Gyrfalcons, Peregrine Falcons, or Common Ravens.
Even though they breed under continuous sunlight in the Arctic, Rough-legged Hawks do take a break between about 11 p.m. and 5 a.m., with less activity and vocalizing.
Rough-legged Hawks have been shown to hunt more in areas experimentally treated with vole urine than in control areas. They may be able to see this waste (as American Kestrels can), which is visible in ultraviolet light, in order to find patches of abundant prey.
Despite a strong affinity for rodents, Rough-legged Hawks were perceived as a threat to poultry up until the early 20th century. Since they are approachable birds that spend their time in open spaces, they were vulnerable to hunting by farmers. It’s now illegal to shoot raptors and most other wild birds under the Migratory Bird Treaty Act.
The oldest Rough-legged Hawk on record, a female, was at least 17 years, 9 months old when found in Illinois in 1979.
