Rough-legged Hawk Project Update: December 2023

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In 2021, Sue Kaehler, Raptor Biologist with Cedar Grove Ornithological Research Station, encouraged Badgerland Bird Alliance (then Madison Audubon) to partner with Neil Paprocki, a PhD student at the University of Idaho. He was gathering information as part of a larger project, “Differential Migration in North American Rough-legged Hawks (Buteo lagopus)”. Neil is focusing on attaching transmitters to Rough-legged Hawks during winter in the Great Plains, Midwest, northeast states, and southeastern Canada.  

Goose Pond Sanctuary staff were excited to participate in this study of a winter bird that frequently visits our area. In December 2021, Graham assisted Neil in trapping Dorothy the Rough-legged Hawk, and in December 2022, Emma assisted Neil in trapping Jeffrey for the Rough-legged Hawk Project.

We were pleased to read an email from Neil on November 5, “Jeffrey the Rough-legged Hawk checks in!”:

Jeffrey, our young dark-morph male (born in 2021) from White River Marsh, checked in this morning from the north shore of Lake Superior. We are looking forward to seeing if he returns to White River Marsh this winter (it would be great to photograph him again), or if he spends time elsewhere. Happy Sunday everyone!

-Neil

a map showing Jeffrey's travels after capture in Wisconsin during December 2022. He spent the summer near Hudson Bay in northern Canada, returning to the upper Midwest recently. His diet at capture listed is meadow vole and white-footed mouse.

On November 17, Neil’s email read, “Dorothy is back!”:

Another update: Dorothy has checked back in today from Thunder Bay, Ontario! She made another great Lake Superior crossing last spring. She also spent the summer in the same location where she spent the summer of 2022 which is exciting (at the northern terminus of her track). The second map shows her cumulative movements since we captured her nearly 2 years ago. Great to have her back online :) Thanks everyone!

Map showing Dorothy's locations since the transmitter was attached in December 2021. She spends summers near Hudson Bay and returns to the area near Goose Pond Sanctuary for the winters. Her diet at capture includes rodents, deer, moose, cat, bird.

A part of Neil’s study involves examining the winter diet of rough-legs.  Graham and Emma helped with the diet examination that involved taking swabs of the beak, talons, and cheeks. We usually think that birds of prey—in this case, Rough-legged Hawks—are feeding on small mammals like meadow voles, deer mice and lemmings. Neil found:

As expected that small mammals dominate the diet (voles, mice, etc. but we’re also seeing significant evidence of scavenging, (e.g. a lot of deer DNA especially. Dorothy had one of the more diverse diets of any bird we analyzed (including the only bird with cat or moose in diet), and it's clear she scavenges on carcasses regularly. Very likely some of the DNA we found on her was from her visiting areas further north prior to us capturing her.

Neil and six other authors recently presented a paper called “Contrasting DNR Metabarcoding Sampling Methods to Describe Rough-legged Hawk Winter Diet.” Just imagine if Dorothy was carrying a camera that allowed us to see the habitats that she uses and what she eats! Mark and Sue recently found a vehicle-killed deer and after securing  DNR approval, Graham and Emma moved the deer to Goose Pond for raptors, coyotes, and badgers to feast on.

Jeffrey near Crex Meadows in Burnett County, WI.

So where have our rough-legs been recently? 

Dorothy near Goose Pond Sanctuary, WI.

Neil reported that Jeffery returned to central Wisconsin and then headed northwest: “He visited Crex Meadows Wildlife Area in Burnett County. Our last report of him was from northwest Minnesota near Grand Forks.”

Neil reported: “Dorothy arrived at Goose Pond on November 24 and left on the 30th.  She has since moved north about 35 miles towards Montello.”  You can see from the map of Goose Pond that she was in the spruce trees at the Manthe family farm on the north side of the east pond. 

“In total, we deployed transmitters on nine Rough-legged Hawks in Wisconsin in 2021 and 2022. Of those, eight are still alive and transmitting, which is really quite impressive and successful compared to other areas we've worked,” said Neil. Data from two birds with satellite transmitters are not included in the movement maps. It is interesting to see that rough-legs migrate across large areas of open water and ice and spend the summer east of Hudson Bay. 

Map of hawk movements (courtesy of Neil Paprocki): Pink is Ruthie (tagged 2021); purple is Dorothy (tagged 2021); blue is Vaughn (tagged 2022); Green is Lowell (tagged 2022); Yellow is Ralphie (tagged 2022); Red is Jeffrey (tagged 2022).

We will keep you posted on their winter travels, and hopefully that you can get out this winter to search for these formidable tundra/prairie raptors.

Neil, Sue, and our Goose Pond team are glad that Badgerland Bird Alliance is participating in this study. Dorothy Haines, who Dorothy the rough-leg was named after, is turning 102 in early January and enjoys learning about her rough-leg! And congratulations to Jeff (Jeffrey) Lang, who the other bird was named for, on his recent retirement from the DNR’s Bureau of Wildlife Management.

by Mark Martin and Susan Foote-Martin, Goose Pond Sanctuary resident managers
Cover image: A Rough-legged Hawk flies through a clear blue sky (photo by Arlene Koziol).