Finches due to swarm over Martha’s Vineyard soon

Evening grosbeaks, aptly named, appear on the Island along with several other finches as they make their way south. — File photo by USFWS

What will the winter be like? Well, the National Weather Service, the “Old Farmer’s Almanac,” and the woolybear caterpillars have all offered the best guesses, but I wouldn’t count on their accuracy. Birders, however, have a prediction you can take to the bank: this will be a winter with lots of finches.

We can say that with such assurance because we’ve already had lots of finches, and more are clearly on the way. Numbers will fluctuate, and the full list of species we can expect is not yet clear. But on the Vineyard as well as in the rest of our region, this will be a bountiful season for these northern birds.

“Finch” is an awkward, generic term lacking scientific precision; but basically it refers to a group of songbirds that are small to medium in size and often colorful — at least in their adult male plumage. In many cases they feature beaks (and life histories) that are adapted to using seeds as a major food source. Our familiar cardinals are finches; American goldfinches and house finches are related species that are likewise familiar to anyone with a bird feeder.

In a phenomenon that is well documented though not fully explained, certain finch species of the northern woodlands sometimes head south during winter in vast numbers. Such influxes, less regular than typical migratory movements, are known as “irruptions.”

Irruptions are unquestionably linked to the food supply (mainly seeds) that these birds depend on. Ornithologists have even had some luck predicting finch irruptions based on summertime seed production in the North. But there’s clearly more to it than that: in most irruption years, only some seed-eating species are on the move, and often birds with similar ecological needs behave very differently during an irruption. These mass movements remain somewhat mysterious, with the timing, movements, and numbers defying accurate prediction.

On the Vineyard, it was clear as early as late August that something was up. Red-breasted nuthatches (which aren’t actually finches, though they often act as if they were) became conspicuous across the Island, in numbers far exceeding the very small population that bred here this past summer. Tiny birds with stubby tails and bold stripes over their eyes, red-breasted nuthatches are not hard to distinguish from white-breasted nuthatches, which are common residents on the Vineyard. The red-breasted species is also easily identified by its call, a persistent, nasal “meep, meep, meep,” like a tin horn. This call remains nearly inescapable on the Island, and this hardy species will likely remain plentiful here through the winter.

More recently, the wave of nuthatches was augmented by flocks of pine siskins, true finches that pushed south during October in large, maybe unprecedented numbers. Closely related to our familiar goldfinches, siskins, when seen well, are distinguished by heavily streaked plumage and a long, pointed bill. Numbers appear to have waned (and, tellingly, huge flocks of siskins are now being reported to the south of us, in southern New Jersey and the DelMarVa Penninsula). But for much of the last month, it seemed that everybody with a feeding station was reporting siskins, and flocks as large as 40 or 50 individuals were noted.

What’s next? Well, while they haven’t yet been recorded this fall on the Island, the season is shaping up to be a good one for evening grosbeaks, a boreal species with yellowish plumage and massive, pale beak. Clearly designed for tackling hard-shelled seeds, the beak allows this species to crush and eat sunflower seeds at a furious clip; a flock of these birds can empty a feeder in minutes. These colorful birds have penetrated into southern New England in modest numbers, with large flocks being reported to the north and west.

Also worth hoping for are the two crossbills, red- and white-winged. These, too, are colorful birds, red in adult male plumage, with yellowish females and streaked immatures. As its name suggests, a crossbill’s salient feature is a beak on which the mandibles cross at the tip, forming a neat little lever used to pry back the flakes of a pine cone, exposing the hidden seeds. If we get really lucky, Island birders might even turn up pine grosbeaks, a truly boreal bird that makes it the Vineyard, on average, only every few decades. But like its relatives, the pine grosbeak is headed our way, and the odds of a least a few making it to the Island look good.

Irruptive finches generally occur in flocks and generally keep on the move. Experienced birders often detect them by their call notes as they pass overhead. Any of these finches could turn up in natural habitat around the Island, especially in conifers (you can bet I’ll be keeping an eye on the large stand of spruces in Correllus State Forest, south and east of the headquarters buildings). But being seed-lovers, northern finches are also apt to drop in on feeding stations, appearing as startling bursts of color and activity, then disappearing as suddenly and inexplicably as they came. Keep your feeders filled (both sunflower and thistle seed, please), keep your hopes up, and keep your eyes open. It’s going to be a finchy winter.