Saturday, October 19, 2013

Hermit Thrush

The Hermit Thrush breeds in the Rocky Mountains and from Alaska across central Canada south to New England and Northern Minnesota, Wisconsin and Michigan. This thrush winters in the southern US and along the Pacific coast south to southern Mexico. This photo is of a migrant Hermit Thrush this October in the Carleton College Arboretum—the tiny buffy tips to the wing coverts indicate this individual was hatched this year. Older birds lack these spots.

Unlike other thrushes (e.g., Wood, Gray-cheeked, Swainson’s), Hermit Thrushes do not cross the Gulf of Mexico. This cold-hearty species arrives on its breeding grounds early in the spring and departs late in the fall. Hermit Thrushes usually migrate by night. Normally Hermits take off about 30 minutes after sunset. Most flights end about 40 minutes before sunrise. I often band Hermits very early or late in the day (Delinger et al. 2012).

Fall migrants prefer migrating in high-pressure weather systems, with clear skies and northerly winds. Curiously, Hermit Thrushes will fly into thunderstorms, “even if doing so results in a reversal of direction.” Each night, they maintain a constant direction (more or less south), changing headings depending on the position of each evening’s sunset, perhaps calibrating an internal magnetic compass (Delinger et al. 2012).

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