Additional reports of evening grosbeaks from across the state are arriving daily. Perhaps you have been one of the lucky ones to have them in your yard. Members of this species are awfully restless in the winter so count yourself fortunate if evening grosbeaks linger for more than a week at your feeder.

I strongly encourage you to learn the distinctive flight calls of evening grosbeaks. Sometimes the note given (often translated as “cleep”) is sweet and other times burry. In either case it is instantly recognizable once you train your ears. Visit http://bit.ly/2fiPyiO for good recordings of the call.

As satisfying as it is to detect an unseen flock of evening grosbeaks overhead, seeing these robust beauties is even better.

The males with their yellow bodies, brown heads with yellow eyebrows, and a large patch of white on each black wing, are stunning. The understated females, with tones of bluish-gray on their body and a large white patch on each black wing, have a beauty of their own. They love sunflower seeds so keep your feeders stocked.

The scientific name of this finch is Coccothraustes vespertinus. The genus name Coccothraustes means “kernel breaker,” certainly appropriate for a bird with a stout, conical beak. The species name vespertinus refers to “evening,” a puzzling claim since these birds are active all day long as anyone lucky enough to have them at a feeder can attest.

The evening reference comes from observations made by a Major Delafield, a U.S. boundary agent in 1823:

“At twilight, the bird which I had before heard to cry in a singular strain, and only at his hour, made its appearance close by my tent, and a flock of about half a dozen perched on the bushes in my encampment … My inference was then, and is now, that this bird dwells in such dark retreats, and leaves them at the approach of night.”

Perhaps Delafield heard some evening grosbeaks as they were going to roost but they certainly do not call only at twilight. Nevertheless, Delafield’s claim of calling restricted to the twilight hours was accepted by ornithologists who dubbed Coccothraustes vespertinus the evening grosbeak for its standardized common name.

Evening grosbeaks are relatively recent arrivals in Maine. This species is originally a bird of western North America. The imminent Massachusetts ornithologist Edward Forbush claims that until the winter of 1889-90, evening grosbeaks were virtually unknown east of Ohio. During that winter an eastward invasion brought these birds into eastern Massachusetts.

A second large invasion came in 1910-11, leading to the gradual establishment of evening grosbeaks as breeding birds in southeastern Canada and the northeastern United States.

Some have suggested that the immigration of evening grosbeaks into the east was facilitated by the spread of box elder trees.

The seeds and buds of box elders are favored by evening grosbeaks. The planting of these trees as ornamentals may have contributed to the invasion of evening grosbeaks to Maine.

Evening grosbeaks were fairly common birds in the 1960s and 1970s in the Northeast. Their success may have resulted from the widespread spruce budworm outbreaks then. Evening grosbeaks feed their young protein-rich insects and spruce budworms are among their favored prey.

Spruce budworm populations go through decades-long patterns of growth and decline. A decline in spruce budworm abundance in the early 1980s is correlated with a steep decline in evening grosbeak abundance. The grosbeak populations continue on a downward slope begun around 1980.

Human impacts are responsible for some evening grosbeak mortality. This species is the 10th-most likely species to be killed from window crashes.

Many evening grosbeaks are killed by cars because the birds come onto roads to collect grit for their gizzards as well as road salt.

Herb Wilson teaches ornithology and other biology courses at Colby College and perches in South China. He welcomes reader comments and questions at

whwilson@colby.edu

Copy the Story Link