A common redpoll perches in the sun. Credit: Courtesy of Bob Duchesne

The birding story of this winter has been the massive finch invasion from Canada. Some of that wave has now washed over Maine and continued south. But the first crop of small finches — American goldfinches and pine siskins — has been replaced with an influx of another small finch: the common redpoll. I hear them everywhere I go. I even saw a few munching seeds outside Hannaford at the Bangor Mall last week.

I realize that not everyone noticed this invasion. Some backyard feeders have been hit hard by the finches. Some have been completely ignored, including mine. But they’re out there. Even though not everyone is aware of it, it’s still interesting to discover that this kind of invasion happens in Maine. We tend to think of migration as a static “birds go south in autumn and north in spring.” But for a lot of birds, the movement is much more chaotic. Birds that eat berries and seeds can go just about anywhere there are berries and seeds. When there’s not enough berries and seeds north of the border, they all come down here. Some keep going.

The Maine Bird Atlas project, being conducted by the Maine Department of Inland Fisheries and Wildlife, is now in its second winter. In summer, volunteers search out all the species that nest in Maine, compiling a comprehensive inventory over this five-year project. But the winter component is only aimed at finding out what parts of the state are being used by Maine’s full-time resident birds plus winter visitors. It only takes a few hours to survey a block to figure out what’s present.

As a dutiful volunteer, I visited the Stud Mill Road east of Milford this weekend. I chanced upon the mother lode of common redpolls. Over the course of a 2 mile walk, I encountered five separate flocks totaling 117 redpolls. The first flock filled the roadside trees with 50 birds, all buzzing and chattering merrily. Redpolls nest in the subarctic region of Canada, where they see few people. To them, we’re just two-legged caribou – nothing to worry about. That means you can often get pretty close without annoying them. I did. Winter birding is fun.

Common redpolls are the same diminutive size as goldfinches and siskins. They are brownish-gray with streaky breasts, black around the bill and a rosy cap. Some males have a pinkish breast. They are prone to traveling in flocks, so if you see one, you’re likely to see a bunch. Sort through them. You might spy a hoary redpoll.

Birding is like panning for gold. If you sift through enough gravel, you sometimes find a nugget. Hoary redpolls are very similar to common redpolls. Some ornithologists believe that they’re just a variation of the common redpoll, but for now, they are considered a separate species. Hoary redpolls are noticeably frostier. Take time to scan through redpoll flocks to see if there’s one that appears whiter than the rest.

Whiteness alone is not enough to confirm a hoary redpoll. There’s a lot of color variation in any flock of redpolls. Some commons are frostier than others. But hoary redpolls have other distinguishing features that help with identification. The breast streaks are much finer, sometimes barely perceptible. Upon close observation, the bill is stubbier – so stubby that you might ask yourself, “How does he eat with that thing?” Hoaries have a whitish rump, whereas commons are a uniform brownish color from the back to the tail.

Hoary redpolls nest farther north than common redpolls, right up to the Canadian Arctic. It’s been years since I’ve seen one, but when I did, it was in a flock of common redpolls devouring the nyjer seed in my backyard feeders. They’re rare, but possible. Several have been reported in Maine this season.

Meanwhile, the invasion of finches has sagged southward. I checked with eBird, an online database of bird sightings run by the Cornell Lab of Ornithology, to see where the bulk of sightings are happening now. The goldfinches and siskins have largely fled northern Maine, and the winter population is now below Bangor. Pine grosbeaks were abundant just a couple of weeks ago, but that lasted only until they exhausted the berry and crabapple crop in our area. Now, it’s off to greener pastures. Southern Maine is seeing more of them this week.

Some finches are still around, though. The invasion continues. And the best thing is – we don’t have to chase these birds. They’re coming to us.

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