Sparrow
Common name originally given to about 23 species of a family of passerine birds found in Eurasia. The name was later applied to more than 50 American species of a different family.
The best-known American sparrow is probably the song sparrow, found throughout most of North America. There are nearly 40 subspecies, ranging in length from 12 to 17 cm (4.7 to 6.7 in), with the largest in Alaska and the smallest around San Francisco Bay. In all the upper surface is some shade of brown, more or less streaked, and the underparts white or buff, streaked with black or brown. The song sparrow's nest, composed of grasses and rootlets lined with fine grasses and long hair, is often placed on the ground. The eggs are variable in color and form; the ground shade is whitish, thickly marked with reddish-brown or lilac.
Another familiar species is the chipping sparrow, 13 cm (5.25 in) long, smaller than most song sparrows. It has a black-streaked, brown back; pale-gray underparts; and (in spring and summer) a bright reddish-brown cap. It is well known for its habit of lining its round, compact nest with horsehairs. Its song, often heard even in the heat of the day, is a simple trill.
The white-crowned sparrow is seen in the eastern United States only as a migrant, but in the west it breeds from Alaska and Canada south to New Mexico in the mountains and to California on the coast; it is a familiar nesting bird even in downtown San Francisco. Depending on the subspecies, it is 16 to 19 cm (6.5 to 7.5 in) long, with a puffy white crown striped with black (buff streaked with dark brown in immature birds), a gray and brown streaked back, gray underparts, and a bright-pink or yellow bill. It is one of the world's most thoroughly studied wild bird species, and much has been learned about its physiology, local song dialects, and migration.
Scientific classification: Sparrows belong to the families Passeridae and Emberizidae of the order Passeriformes. The song sparrow is classified as Melospiza melodia, the chipping sparrow as Spizella passerina, and the white-crowned sparrow as Zonotrichia leucophrys.