Spizella pusilla

Field Sparrow

Family: Passerellidae · Class: Aves · Order: Passeriformes

The Field Sparrow is a small songbird measuring 12-15 cm (4.7-5.9 inches) in length with a wingspan of 19-22 cm (7.5-8.7 inches) and weighing 11-15 grams. Adults display a distinctive rusty crown and gray face with a prominent white eye-ring. The bill is bright pink-orange, contrasting with the gray-brown upperparts that show rusty streaking. The underparts are pale gray to buff with a white belly and throat. Juveniles appear similar but with less distinct markings and duller coloration. The species exhibits minimal sexual dimorphism, though males may show slightly more vibrant crown coloration. Historically, Field Sparrows bred across much of the eastern United States and southeastern Canada. In California, this species is considered a rare vagrant, with scattered records primarily from the southeastern desert regions and Central Valley during migration periods. Most California sightings occur between September and April, with birds typically found in desert scrub habitat near the Colorado River and in agricultural areas of the Imperial Valley. The species has also been documented occasionally in riparian corridors and weedy fields throughout the state's interior valleys. Field Sparrows inhabit open grasslands, prairies, old fields, and early successional habitats with scattered shrubs and trees. They prefer areas with approximately 25-75% shrub cover interspersed with herbaceous openings. The species thrives in habitat mosaics created by agricultural abandonment, selective timber harvests, and natural disturbances. In their primary range, they occupy elevations from sea level to approximately 1,500 meters, favoring areas with native bunch grasses and forb communities. During the breeding season, Field Sparrows are primarily granivorous, consuming seeds of grasses and forbs including Panicum, Setaria, and Amaranthus species. They supplement their diet with insects, particularly during the breeding season when feeding young. The species typically produces 2-3 broods per year from April through August. Females construct cup-shaped nests in low shrubs or on the ground, laying 3-5 pale blue eggs with brown spots. Incubation lasts 11-12 days, with nestlings fledging after 7-8 days. Males establish territories through persistent singing from exposed perches, delivering their characteristic accelerating trill. The Field Sparrow is not federally listed and maintains stable populations across most of its range, though long-term breeding bird survey data indicates regional declines in some areas due to habitat loss and agricultural intensification. The North American Bird Conservation Initiative considers the species a Common Bird in Steep Decline, with populations decreasing by approximately 46% since 1970 according to Partners in Flight. In California, the species remains a rare visitor with no established breeding populations. Primary threats include conversion of grassland habitat to intensive agriculture, urban development, and suppression of natural fire cycles that maintain early successional habitats. Conservation efforts focus on maintaining diverse grassland management practices and preserving habitat corridors that support dispersal during migration.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.