Northern Cardinals have started singing already in my backyard, but I didn’t see any of those bright red birds on a recent trip to Sax-Zim bog in northern Minnesota. It might get a little too cold for them up there, and they might not find enough to eat in the spruce forest. Instead, the little red birds that brighten up the forest there are Common and Hoary Redpolls and Purple and House Finches.
Redpolls migrate in an “eruptive” fashion, with large flocks moving from one area to another, distant one as food supplies diminish. They ventured at least as far south as southern Minnesota during our past two extremely cold winters, but they typically winter almost as far north as they breed. Redpolls have phenomenal heat generation capability and can stay warm (by shivering) at temperatures as low as -65F ( or -54C). In Alaska, they might take refuge from arctic storms by burrowing into a snowbank overnight — kind of like husky dogs would.
Purple Finches aren’t quite as tough. They desert their Canadian forest summer breeding grounds to winter in the eastern U.S., where they unfortunately compete with House Finches and House Sparrows for food and space.