Sunday, October 19, 2014

First White-throats in Missouri

As our autumn colors begin to peak, I encountered the first white-throated sparrows of the season at the Fourm Nature Area, in Columbia.  As usual, it was their distinctive song that caught my attention, a tune that will diminish in winter and then build to a frenzy in early spring.

Summer residents of open forest across Canada, the Great Lakes region and New England, these stocky sparrows are among the most common winter residents in the American Heartland and Southeastern States.  Though they migrate across the Great Plains and Intermountain West, white-throats have begun to winter along the Front Range urban corridor over the past decade; they have long been winter residents in coastal regions of California.  Best found along wood borders near thickets and brushy fields, these hardy birds are easily drawn to feeding stations where they scour the ground for fallen seed.

Songbirds and shorebirds migrate in response to the solar cycle and their dates of arrival and departure are fairly predictable each year; white-throated sparrows generally begin to appear in Missouri in mid October and most will depart for Canada by mid-late April.  Waterfowl, on their other hand, migrate in response to food availability and their schedule is far more variable; indeed, as our climate warms, their autumn migrations may be delayed and their journeys will likely be shortened.  On the other hand, sudden, intense storms with heavy snow and severe cold may send them south in huge flocks, sometimes well ahead of their usual schedule.