Schiess: Arctic Redpolls Invade southeast Idaho
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With a group of 20 small birds attacking the seeds on the birch trees at Beaver Dick Park, seeds littered the snow turning it into a tan brown carpet.
“Common Redpolls,” I thought as I got out of the truck for a closer look. They moved a little higher in the trees, but did not stop their eating in the bitter cold of a minus 12 degrees.
This winter is the first time I had seen flocks of them since the winter of 2012-2013 when they invaded most birch trees in the Upper Snake River Valley. While following big game migrations from the mountains two weeks ago, I found a small flock on the desert, north of the St. Anthony Sand Dunes. They have also been recorded in Ashton and on the Rexburg and Howe Christmas Bird Counts. In the last few days they have been visiting my backyard to feed on Niger seeds.
Common Redpolls are an Arctic breeding bird with most of their summer range above the Arctic Circle. They are not migratory, but are one of the irruption species, meaning they move to find food. At times they will join mixed flocks of other finches in their movements and are usually seen with American Goldfinch and Pine Siskins. Their irruptions usually coincide with a successful breeding season followed by winter food storage in Canada and Alaska.
When birch and alder trees fail to produce large amounts of catkins for the redpolls’ winter food they head south in large numbers. Three years ago flocks from 30 to 100 were observed along the highways of southeastern Idaho. Most observed redpolls are singles or small groups mixed with other wintering finches.
Redpolls have several interesting habits and adaptations. One is they have a sac inside their throat area where they store seeds. During the winter they may knock seeds off plants, swoop down, store the food in these sacs, then fly to a more secluded area to shell and eat seeds. On windswept stubble fields, they may forage in waves of large flocks across the fields.
Another interesting habit for them is during cold weather they will fly from a high tree diving into the deep snow. They will then create a snow tunnel about a foot long as a roosting chamber. This allows the snow to act as insulation against the cold. Ruffed Grouse and Boy Scouts use these same techniques – though Boy Scouts shouldn’t dive into the snow but dig snow caves.
Attracting these itinerant birds to your backyard will be hit and miss. Mature birch trees will provide them with their favorite food, but they will also visit Niger (thistle) seed sacks as well as sunflower feeders. Large flocks have been seen around Rexburg, St. Anthony, Ashton and most cemeteries that have birch trees in them. Recently, large flocks have been seen in alder trees along the Henrys Fork of the Snake River and the Little Lost River north of Howe.
If they visit your backyard in large flocks you will know immediately while small groups may go unnoticed. Large groups will empty your feeders fast while keeping up a constant chatter.
I love the chatter of kids and birds; hopefully this will be a winter when more Common Redpolls stay all winter and will entertain me during the bitter cold months.