The winter of 2021-22 will go down in the bird record books for the irruption of Common Redpolls in Wisconsin. Redpolls are one of our favorite winter birds and we enjoy seeing these acrobatic songbirds.

The Cornell Laboratory of Ornithology (CLO) states that Common Redpolls are energetic little birds that forage in flocks, gleaning, fluttering, or hanging upside down in the farthest tips of tree branches. Like many finches, they have an undulating, up-and-down pattern when they fly. To keep order in flocks, redpolls have several ways of indicating their intentions. When quarreling with flockmates, a redpoll fluffs its plumage, faces its adversary, and opens its bill, sometimes jutting its chin to display the black face patch.

Sam Robbins wrote in Wisconsin Birdlife that Common Redpolls are “fairly common winter resident south. Irregular.”

Bird watchers on the Wisconsin Birding Network (Wisbirdn) reported that their numbers were increasing in late January in southern Wisconsin. At Goose Pond there were seven eBird reports of redpolls at Goose Pond beginning in January 2022.

At Goose Pond Sanctuary the first eBird record for Common Redpolls was 50 individuals seen in 1997 by Aaron Stutz. Additional records since 1997 are one in 2009, two in 2017, nine in 2018, and two in 2020.

There was also a Redpoll invasion in 2018, when Maddie Dumas, land steward, found five Redpolls at the Prairie Lane residence and we found 110 (Goose Pond high count) at the Kampen Road residence on the Great Backyard Bird Count.

A search for information on the winter diet of Common Redpolls found that they eat birch, tamarack, and alder seeds; feed at ground, platform, hopper and tube feeders on millet, thistle or nyjer seed, and black oil sunflowers or sunflower chips; evening primrose in prairie restorations; and lamb’s quarter in weedy fields.

Common Redpolls at a feeder. *Photo by Courtney Celley/USFWS Midwest Region*

On February 28th, 2022 JD Arnston counted 48 Redpolls in the plum thicket where the railroad tracks cross Kampen Road, and on March 3 he found 44 in the same location. Graham Steinhauer and Calla Norris had two at their feeders on Prairie Lane and one bird was at the Kampen Road residence.

Mark asked JD what he thought the birds were feeding on. He was not sure but said that the flock would move back and forth from the plum thicket to the prairie restoration in the Lapinski-Kitze Prairie that germinated in 2020. Our guess is that the flock was feeding on evening primrose, a biennial, that was abundant in 2021, the second growing season, and on lamb’s quarter, an annual, that soon will be crowded out by the prairie plants.

On February 23, 2013, we found 400 Common Redpolls at a food plot dominated by lamb’s quarters at our cabin near Rio. We also eBirded a Sharp-shinned Hawk that day that was hunting for redpolls. Mark and William Damm also remember finding hundreds of Common Redpolls in a recently acquired DNR, fallow cropland field dominated by lamb’s quarters at the French Creek Wildlife Area on the Pardeeville Christmas Bird Count.

Can you spot the Common Redpolls amongst the other winter birders at this Sax Xim Bog feeder? *Photo by Mark Martin*

Common Redpoll range. Map provided by Cornell Lab of Ornithology

The Cornell Laboratory for Ornithology reports that Common Redpolls are numerous. Partners in Flight estimates a global breeding population of 160 million, with 17% spending some part of the year in Canada, and 22% wintering in the U.S. They rate a 7 out of 20 on the Continental Concern Score and they are not on the 2014 State of the Birds Watch List. These birds breed in the far north, away from large numbers of humans and many of their environmental impacts. When they come south to visit more densely populated areas, they can succumb to salmonella infections at feeders. It remains to be seen what changes climate change may cause for their boreal and tundra habitat.

Cool Facts
- During winter, some Common Redpolls tunnel into the snow to stay warm during the night. Tunnels may be more than a foot long and 4 inches under the insulating snow.
- Next time you have access to a globe, take a look at it from the top. Common Redpolls breed around the world in the lands that ring the Arctic Ocean. There’s a lot of land up there! Though many of us struggle to see a few redpolls each winter, worldwide their numbers are estimated in the tens of millions.
- Animal behaviorists commonly test an animal’s intelligence by seeing if it can pull in a string to get at a hanging piece of food. Common Redpolls pass this test with no trouble. They’ve also been seen shaking the seeds out of birch catkins, then dropping to the ground to pick them up from the flat snow surface.
- Redpolls have throat pouches for temporarily storing seeds. They may fill their pouches with seeds quickly then fly away to swallow the seeds in a more protected, warmer spot.
- Some studies show that in winter redpolls subsist almost entirely on a diet of birch seeds. They eat up to 42 percent of their body mass every day. They can store up to about 2 grams (0.07 oz.) of seeds in a stretchy part of their esophagus, enough for about a quarter of their daily energy requirement.
- A few banding records have shown that some Common Redpolls are incredibly wide ranging. Among them, a bird banded in Michigan was recovered in Siberia; others in Alaska have been recovered in the eastern U.S., and a redpoll banded in Belgium was found 2 years later in China.
- Common Redpolls can survive temperatures of –65 degrees Fahrenheit. A study in Alaska found Redpolls put on about 31 percent more plumage by weight in November than they did in July.

One area to visit in winter in years of few Redpolls in southern Wisconsin is Sax-Zim Bog northwest of Duluth, MN. This spring we are planting tamarack trees at our cabin and are looking forward to planting weedy food plots at Goose Pond to benefit are friends from the tundra.

Written by Mark Martin and Susan Foote-Martin, Goose Pond Sanctuary resident co-managers

Cover photo by Ott Rebane FCC