Bird of the Week

Photo courtesy Byron Greco

This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the Cassin’s finch.

The Cassin’s is a finch of the western mountains of North America, where it is a year-round resident of evergreen and aspen forests. Here, they may migrate elevationally from their breeding territory, moving downslope in winter months. Except during nesting season, Cassin’s finches usually travel in small flocks, often in the company of crossbills, grosbeaks, siskins and other finches. They do visit backyard sunflower feeders.

The heavy, conical bill of the Cassin’s is well suited for extracting the seeds from pine cones, which make up a large part of its diet. In spring, these finches feed heavily on the buds of quaking aspen. They also have a craving for salt, which they satisfy at mineral deposits.

The male Cassin’s has a streaked brown back with a rosy-pink wash on the throat, plain breast, back and rump. He can erect his bright red crown feathers, giving him a peaked-head look. Females and immature males are streaky brown with white undersides cut by short, crisp streaks. Both sexes show thin white eye rings and notched tails.

It can be difficult to distinguish the Cassin’s from the similarly marked house finch. House finches are generally smaller and slimmer, with more rounded heads. A close look will show the male house finch wearing a brown cap.

John Cassin, for whom this finch is named, was a prominent 19th century ornithologist. Worldwide, nine bird species are named for him.

For reasons not well understood, the Cassin’s finch is experiencing population declines.

For information on future events, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.

This story was posted on November 22, 2020.