BIRD SPECIES AND DISTRIBUTIONS IN YUKON-CHARLEY RIVERS NATIONAL PRESERVE
White-crowned Sparrow (Zonotrichia leucophrys)
The family Emberizidae encompasses a variety of widespread species, including sparrows, juncos, towhees, longspurs and Emberizid buntings. Sparrows are generally small, brown-bodied birds with streaked backs and conical bills for eating seeds. They feed on or near the ground but each species has its own habitat preferences. The word "sparrow" is derived from the Anglo-Saxon for "flutterer," in reference to their active flight. Sparrows may be difficult to identify as most species display a variety of immature, regional and/or seasonal plumages. Head and breast patterns, along with song and habitat are the most helpful in their identification. The genus Zonotrichia contains many of the largest species of sparrows (White-crowned, White-throated and Golden-crowned Sparrows) with large, heavy bodies and long tails.
Descriptions: The White-crowned Sparrow occurs in most boreal forest habitats, particularly those with sparse trees and dense shrubs. At 18cm, these sparrows are a large slender species with a long tail and neck. Although their black-and-white-striped crown is distinctive, many variations in plumage exist within this species. However, both sexes are similar in appearance. As the name implies, the top of the head displays two broad, black stripes separated by a median, broad white stripe but in juvenile birds, the crown is composed of two dark brown stripes with a tan, median stripe. Often, they will raise the feathers of their conspicuous crowns. In all plumages, a thick white eyebrow stripe is offset by the dark eyeline. Generally, the throat is whitish and the underparts and nape are gray. While the flanks and tail are solid brown, the back and wings are streaked in grayish-brown. Two white wing bars garnish the wings. Also characteristic are their pale pinkish-orange bill and flesh-colored legs.
Vocalizations: The song of the White-crowned Sparrow is composed of clear whistles and buzzy trills but varies geographically. Often given during winter, the lazy song notes may sound like "feee, odi, odi, zeeeee, zaaaaaa, zooo" or "seee, sitli, sitli, te-te-te-te-te, zrrr." The call is a loud "pink" note. On the fly, the call is a sharp "tseep."
Nests: Nests are cup-shaped and constructed by the female in 2-9 days. After selecting the nest site, either on the ground or in low shrubs, the female assembles the nest of grasses, twigs rootlets, forbs, leaves and shredded bark. Lined with fine materials, the nest provides a soft haven for the 2-6, 21mm eggs of the clutch. Eggs may be pale greenish-blue to creamy white and are marked in reddish browns. Unaided, the female incubates the clutch for 11-14 days and does the brooding. If disturbed, the female may run mouse-like off of the nest. Initially, (for the first 3-4 days post-hatching) young birds are fed only by the female. Later, the male also assists in rearing the young. Often, the male will assume care for the first brood while the female begins another nest. Young birds fledge 7-12 days post-hatching.
Diet: An adaptable generalist, the White-crowned Sparrow dines on a variety of food items: insects, spiders, berries, forb and grass seeds, moss capsules, blossoms and fresh leaves. They forage by gleaning food from the ground and foliage as they walk along the forest floor. In addition, these sparrows hawk flying insects by swooping after them from their perches.
Distribution: In winter, White-crowned Sparrow forms stable flocks of 10-50 birds with Golden-crowned Sparrows in central Mexico. These flocks display a strong site-attachment and fidelity to a particular wintering territory. In some non-migratory populations, a breeding pair may stay on the same territory year-round and mate for life! During the breeding season in the far north, males tend to arrive 2-3 weeks before females. The breeding range extends throughout most of mainland Alaska, Yukon and Northwest Territories and across northern Canada east to Nova Scotia, and southward throughout British Columbia to spotty localities among the western states. During the Yukon-Charley Rivers National Preserve Bird Inventory, June 1999 and 2000, these birds were detected in all ecological units within Yukon-Charley Rivers National Preserve, and were the fourth most abundant bird in the Preserve! They occur at their highest abundance in the open, brushy habitats of Three Fingers Subalpine Basin (TF) and the Upper Charley Valleys (UC) ecological units.
|Density of White-crowned Sparrows by detailed ecological unit in Yukon-Charley Rivers National Preserve, Alaska, Avian Inventory, June 1999 and 2000.|