BIRD OF THE WEEK: 2/27/2015 SCIENTIFIC NAME: Coccothraustes vespertinus
POPULATION: 4 million
TREND: Decreasing
HABITAT: Breeds in coniferous and mixed forests. Wanders widely during winter.

Evening Grosbeak map, NatureServeAlthough the Evening Grosbeak is a noisy bird, constantly vocalizing with piercing calls and burry chirp notes, it does not produce complex songs to attract a mate or defend territory. Its genus name, Coccothraustes, means “kernel-cracker,” reflecting its ability to crack large seeds with its powerful bill.

In the last 20 years Evening Grosbeaks have been declining throughout their range, which led to the species' inclusion on the State of the Birds 2014 Watch List for the first time, along with other at-risk species such as Chuck-will's-widow and Bobolink.

Evening Grosbeaks are social and somewhat nomadic; flocks may wander widely in response to changing food supplies. These seasonal movements, or irruptions, occur during the fall and winter.

People lucky enough to have Evening Grosbeaks visiting their feeders can be in for a major investment. A flock can literally consume hundreds of pounds of sunflower seeds over the course of a winter!


Evening Grosbeak female, Dennis Dore

Evening Grosbeak female by Dennis Dore

Grosbeaks Gaining (and Losing) Ground

The species expanded rapidly across the eastern U.S. during the 20th century, possibly due to the increased planting of box elder, a major food source, in cities. Unfortunately, the bird has almost disappeared from the east once again, and the specific cause is unknown.

Potential causes of the Evening Grosbeak's decline are tar sands exploitation, which has destroyed large swaths of its boreal breeding habitat, shared by birds such as Blackpoll Warbler and Swainson's Thrush. Global warming may reduce boreal habitat even further in future years.

Behind the Grosbeak's Decline

Pesticides used to control spruce budworm, an important food for Evening Grosbeak and other birds like Magnolia Warbler, may also be a factor in its decline.

Other problems may include forest management that favors fast-growing softwood trees like pines for paper and wood products, rather than slower-growing, seed-producing hardwoods such as maple and box elder.

Large numbers of Evening Grosbeaks are killed by window collisions and by cars during winter, when they gather on roadsides to pick up road salt and grit.

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