Wednesday, May 20, 2009

In the backyard... Evening Grosbeak

Evening GrosbeakEvening Grosbeak, male, Forest Grove, Oregon on 15 May 2009 by Greg Gillson.


This large, stocky finch breeds widely in the forested mountains of the Pacific Northwest, where they feed on pine cones and other fruit, seeds, and insects. In winter, these birds often move to lowland towns throughout the region. However their winter travels are irregular and unpredictable. Some winters they may be common at backyard feeders. In other winters they may be absent.

Each May, however, these birds descend en mass to the lowlands west of the Cascades. Here they feed on the buds and young seeds of native maples and imported elm trees. At this time, they will move in and eat a tremendous amount of sunflower seeds at your feeder. By mid-June, most are gone back to the mountains, probably following the budding of the maples upslope as spring moves up the mountains.

Throughout the year, their loud, descending whistles (both clear and buzzy) announce their presence. However, many times they are glimpsed only in noisy flocks of 6-30 birds flying high overhead.

The bold white patches on the black wings really stand out on both sexes. The males have a smoky black head that pales into the yellow underparts. There is a blaze of yellow across the forehead. The huge bill is bone white, but has a slightly greenish hue in summer. Females lack the black head, and the body plumage is more of a pale gray with only a hint of yellow.

The breeding range of Evening Grosbeaks is the Rocky Mountains from northern British Columbia south through western Mexico, across the boreal forests of Canada to the Atlantic provinces, south to the northern portions of the northern states. The also breed in Western mountains from British Columbia south to central California, including the Coast Range. In winter, they move south, regularly to Pennsylvania and Iowa and other states at that latitude, irregularly to the southern states in the United States.