With 'irruption' birds, it's feast or famine
Thus far this past late fall and early winter, my backyard bird feeding station has attracted the usual assortment of wild birds. Aside from a small band of pine grosbeaks that showed up for a few days in a row, I have yet to see any large influxes of other wintertime birds that often occur each year.
Common redpolls are one such bird that we associate with these "irruptions," or, put another way, the sudden uptick of a species' abundance, which generally means that environmental conditions aren't suitable where "irruptive" species typically inhabit at any given time and place.
Redpolls belong to a group of birds collectively called finches, and are closely related to pine grosbeaks, evening grosbeaks, pine siskins, American goldfinches, and crossbills.
Found throughout the globe's northern latitudes, common redpolls are a welcome sight to most anyone's birdfeeders. About the size of black-capped chickadees, common redpolls sport dark faces and black throat patches, similar to chickadees. Nonetheless, it's their distinctive streaked flanks and reddish brown heads (the latter characteristic being the reason for their name "redpoll") that helps set them apart from other species of birds.
Birds commonly associated with winter irruptions include pine grosbeaks, pine siskins, purple finches, evening grosbeaks, red crossbills, and white-winged crossbills.
And some species that will often shift to different wintering areas are black-capped chickadees, blue jays, red-breasted nuthatches, Bohemian waxwings, and varied thrushes. Varied thrushes, for example, though very rare in Minnesota, do show up from time to time. A couple of people in the Grand Rapids area recently posted photos of a lone varied thrush on a popular local Facebook site.
Common redpolls enjoy feeding on birch and alder catkins. So, when a preferred food source is depleted or naturally low in availability and abundance, huge numbers of redpolls will disperse from their preferred wintering areas in search for more suitable conditions and food.
Cornell Lab of Ornithology's website reports that common redpolls are abundant and a species of with a "low" continental conservation concern score. With a worldwide breeding population at around 160 million, ". . . with 17 percent spending some part of the year in Canada, and 22 percent wintering in the U.S."
It should come as no surprise that common redpolls are uncommon here in Minnesota for half the year. After all, their breeding range includes mostly the Arctic Circle, whereas winter range extends south to the northern-tier states.
Once they arrive on their breeding grounds, courtship, nesting, and rearing young commences quickly to take advantage of longer daylight and abundant insects, seeds, and fruit. Interestingly, during the breeding and nesting season, females are the dominant sex. Females find suitable nest sites and build nests on their own, and perform most of the nestling rearing duties. Male redpolls do assist with feeding duties, but their participation varies.
The sudden wintertime appearance of the northern-breeding common redpoll reminds me of the winter of 2001-02, when huge flocks of common redpolls dominated my feeders at the Audubon property that I formerly managed southeast of Warren. At the time, I was feeding both thistle seed and black-oil sunflower seed. Believe me, between them and squirrels, it was difficult keeping the feeders filled. Yet, almost as quickly as they appeared, the flocks gradually diminished until they migrated north once again.
Wintertime is always a good time to reflect, while appreciating Mother Nature in all her quiet grandeur. For me, the slower pace locked in snow and ice is a welcome reprieve from the busier warmer months of spring, summer, and fall.
And though this winter is shaping up to be lonely and long for yours truly, perhaps hordes of common redpolls will arrive soon to restore all our faith in better times ahead, wild birds everywhere, and plenty of seed to go around — as we get out and enjoy the great outdoors.