This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the American tree sparrow.
Behavior, location and time of year all come into play when identifying similar-looking sparrow species. The American tree sparrow is one of our winter birds. In appearance, it shares the rufous cap and unstreaked underparts of the chipping sparrow, but these two species are rarely seen here at the same time of year.
In addition to its reddish cap, identifying traits of the American tree sparrow include a reddish stripe behind the eye, a dark central spot on its gray chest, long tail, two white wing bars and a two-toned bill, dark on top and light on the bottom.
Despite their name, these sparrows are not usually associated with trees. They forage on the ground, often in small flocks during winter. In semi-open shrubby habitat, they scratch the ground, hop up on weeds and beat the seedheads of grasses with their wings to release the seeds. To survive, they need to consume an amount equal to 30 percent of their weight each day.
Long-distance migrants, most of their breeding range is in scrubby areas north of the tree line on the Arctic tundra. They typically nest on the ground, not in trees. Even in winter, most of the population occurs in northern states and southern Canada. We are close to the edge of their southern range.
Breeding so far north, where insects are in abundance in summer and human disturbance is minimal, has been a good survival strategy for these birds.
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