This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the vesper sparrow.
The peak chorus of birdsong occurs in the early hours of morning. The sweet, musical song of the vesper sparrow is also often heard at twilight, the time of day of vespers. This Christian service which ends the day in prayers and song inspired the common name of the vesper sparrow.
Both the Greek and Latin words in its scientific name, Pooecetes gramineus, which translate as grass-lover and grass dwelling, refer to the habitat where this bird is found.
This is a bird of dry landscapes with short, sparse grass and scattered shrubs. It can be found in mountain meadows, grassy mesas and sagebrush steppe, often using fence lines and posts to perch and sing.
In these habitats it scratches the ground for the seeds of grasses, weeds and grains. In summer it adds insects and spiders to its diet, aiding the farmer by eating many crop-destroying insects and weed seeds. With water scarce, it takes frequent dust baths to keep its feathers free of oil and parasites.
Typically solitary, this sparrow prefers to walk or run over flying. In courtship displays, the male runs after a female with wings raised and then jumps into the air while bursting into song. Who could resist? The female makes a ground nest in a shallow depression concealed next to a clump of vegetation, log or branch.
Like the dark-eyed junco, this sparrow flashes the white outer edges of its tail feathers in flight. It is relatively large, has a prominent white eyering and a streaked chest. A rufous-colored shoulder patch can be hard to see. It is not as shy as many ground-dwelling sparrows and often feeds at roadside edges.
We find vesper sparrows here in spring and summer. By October most have left for winter homes in the southern United States and Mexico. As is true for several grassland species, loss of habitat has caused population declines in many areas.
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