One of the most common winter sparrows,
the white-crowned typically occurs in flocks, which may involve more than
100 birds. They feed in short grass or open areas adjacent to woodlands,
hedgerows, or brush piles. They may pop out in response to pishing and raise
their crown feathers when agitated.
Polytypic. Length 7" (18 cm).
Identification For bill color, see sidebar below; whitish throat; brownish upperparts; mostly pale gray underparts. Adult: black-and-white striped crown. Immature: tan and brownish head stripes. Juvenile: Brown and buff head; streaked underparts.
Geographic Variation The white-crowned
sparrow is divided into 3 well-defined subspecies groups: "dark-lored" (Rocky Mountain oriantha and eastern leucophrys), "pacific" (northern pugetensis and southern nuttalli), and "Gambel's" (western gambelli). Individual subspecies are often not identifiable in the field. The region around the lores gives the best first clue. The median crown stripe meets the eye line at the base of the maxilla in the "dark-lored" birds; the supercilium is pinched off and the supraloral region is black. In "pacific" and "Gambel's," the white supercilium meets the gray lores and the supercilium is not pinched off. Judge the bill color, carefully, too: yellow in "pacific," orange in "Gambel's" and pink in "dark-lored." "Pacific" birds often show a prominent malar stripe, rare in the others.
Note as well that the primary
extension is comparatively short in "pacific," longest in "Gambel's", and intermediate to longish in "dark-lored." "Pacific" lacks gray striping on its back, showing only dark brown and tan; gray striping is fairly prominent on the back of "Gambel's" and "dark-lored." "Pacific" also has more brownish coloration to its breast and flanks.
First-winter birds show a distinctive
difference that can be very hard to spot in the field: the first-winter "pacific" has a small patch of yellow feathers right at the bend of its wing; on "dark-lored" and "Gambel's," this
patch is white.
Source: National Geographic