Yesterday afternoon, with bright sunshine streaming through the frigid air, a flock of songbirds alighted at our backyard feeder. Smaller and slimmer than sparrows, they were heavily streaked, like female house finches, but their markings were cleaner and darker. As they moved about the feeder, flashes of yellow appeared on their wings and at the base of their notched tails; combined with their thin bill and pale wing bars, the markings gave the impression that they might be yellow-rumped warblers.
In fact, these amiable birds were pine siskins, small members of the finch family. After breeding in the vast coniferous forests of Canada, New England and the western mountains, they roam about in large flocks during the colder months. An irruptive species, pine siskins are very erratic in their movements throughout the central and eastern U.S. and their numbers vary widely from winter to winter, depending on the seed crop in their home territory.
When they do appear, these gregarious birds are usually found in large flocks, often in the company of goldfinches, crossbills or redpolls. Their rising, wheezy call aids identification and their flight is equally distinctive; while siskin flocks undulate, in the manner of goldfinches, they also close in and spread out in rhythmic sequence, accentuating their cooperative spirit. Indeed, while many bird species congregate during the winter months, pine siskins tolerate one another during the breeding season as well, often placing their shallow, cup-shaped nests in close proximity. Just another species for humans to emulate.
