A Closer Look At The Varied Thrush
This particular bird did not display what Audubon referred to as its "desultory manner" when he wrote:". . . they flit through the forest in small flocks, frequenting usually low trees, on which they perch in perfect silence, and are at times very timorous and difficult of approach, having all the shy sagacity of the Robin, and appearing at all times in a very desultory manner."
Audubon also recorded that naturalists with Captain Cook's third expedition discovered the Varied Thrush, which the Chinooks called "Ammeskuk". This cover-bird for Sibley's Field Guide to Birds: Western North America is somewhat similar to the American Robin but has a dark breast band, orange eye stripe, and orange wing bars. The female, pictured above, is duller and slightly smaller than the male. The Varied Thrush is a characteristic bird of the mature, dark coniferous forests of the Pacific Northwest. It is an altitudinal migrant.
In winter, its diet becomes especially dependant upon fruits and berries, but also upon seeds, acorns, and other nuts. During migration, cultivated food sources such as berry patches, apples, and olives attract it. Since 1988, Varied Thrushes have shown a remarkable biennial cycle, increasing in numbers one year, and decreasing the next. (See Wells J. V. and Rosneberg K.V. 1997. The Rise and Fall of the Varied Thrush. Birdscope, Spring 1996, Volume 10, Number 2: 1-2.) Since Varied Thrushes like acorns, and many species of oak produce acorns in regular two-year cycles, these researchers theorized that the cyclic changes in Varied Thrush abundance result from changes in acorn production. Clearly, this is a low census year so watch for them to irrupt next year.
The Varied Thrush breeds from Alaska and Yukon south to Oregon, California, Idaho, and Montana and spends winters from coastal Alaska southward. Known for its vagrant habits, this species often wanders out of its normal winter range to show up at feeders throughout eastern North America and the southwestern United States. One pale individual turned up in England in 1982.
They are not endangered in any portion of their range, but deforestation and clear cutting threaten their habitat, although they may benefit from laws protecting the Spotted Owl. A closer look at a flock of American Robins foraging in an open area might reward you with the sight of this winter visitor. Also, watch for this bird in wooded areas along streams where you might get an opportunity to photograph its "desultory manner".
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