Evening Grosbeak

On the wild side—December, 2013

by Tina Mitchell

Often moving in large, noisy flocks, Evening Grosbeaks rarely go unnoticed when they arrive.  They announce their presence with loud, trilling call notes that remind me of referee whistles.  Once they come into view, there can be no doubting their identification. The mustard-colored males (left) have dark hoods and black wings and tails; a stunning white patch looks like a white saddle on the lower back when the wings are closed.  In flight, this white patch seems to shine on their dark wings.  Their massive pale beaks can hardly be overlooked.  The yellow “eyebrows” make the males look as if they’re scowling at the world.  Females (right) can barely compete with the flashy males—mostly  gray with a light wash of yellow, and black wings and tails with splotches of white.  These plumages remain constant throughout the year, although both males’ and females’ beaks take on a greenish cast in breeding season.

Evening Grosbeaks breed in the high country beginning in late May; as a result, they leave our lower-altitude habitats around mid-May, heading for stands of ponderosa pines, Douglas-firs, and Engelmann spruces.  After the young fledge and can fly reasonable well, we begin to see family groups again in our area, starting in early August.  These families are easy to spot since the adults often feed the begging fledglings—which look like the females—well into September.  Evening Grosbeaks winter in a wide variety of habitats—oak-pine environments, pinyon/junipers, and even in urban and suburban areas (especially where feeders provide sunflower seeds).

These robust birds dine mostly on seeds, with some berries, small fruits, and—in warmer months—insects and buds of deciduous trees.  At bird feeders, they are especially fond of sunflower seeds.  Their huge bills help them to crack open large seeds with ease.  Sometimes smaller birds follow them around to pick up the crumbs that the grosbeaks deign to leave behind.

The Evening Grosbeak’s scientific name—Coccothraustes vespertinus—in part reflects its eating habits and its massive beak.  The genus name, Coccothraustes, means “seed crusher” (from Greek, kokkos—grain or seed—and thrauo—to break in pieces).  Its common name of “grosbeak” also reflects this massive beak—derived from French gros (large) and bec (beak).  Unfortunately, the other aspects of its name aren’t quite as clear.  The species name, vespertina, comes from Latin for “of the evening.”  A similar reference exists  in the common name, suggesting that it sings or is otherwise more active in the evening.  Well, it’s hard to know what those wacky taxonomists were thinking there, since Evening Grosbeaks don’t really have much of a song—just those noisy “referee whistle” calls.  And they can be active from dawn to dusk.  Alas—some things are destined to remain a mystery…

In central Colorado, 5 species share the common name “grosbeak.”  But they are not all closely related.  If you have a bird field guide, perhaps you’ve noticed that some grosbeaks are listed earlier in the book than the others.  Three species—Black-headed, Rose-breasted (which occasionally pass through our area), and Blue Grosbeaks (which nest along the Arkansas River)—are in the cardinal family and taxonomically listed earlier in the guide.  Two other species—Pine (found in the high country) and Evening Grosbeaks—are in the finch family, appearing near the end of the field guide.  This latter classification has always struck me as a bit funny, since, as one birder noted, Evening Grosbeaks look rather like sumo wrestlers, compared to most of the delicate finches.

During the winter, Evening Grosbeaks often wander erratically throughout much of our state and throughout the U.S.  So if you don’t see them around your house today—look and listen again tomorrow and the day after that and the day after that…  You just never know when these showy, noisy birds might make an appearance!

You can learn more about this species here.