The thick-billed fox sparrow group comprises the peculiarly large-billed Sierra Nevadan taxa in the genus Passerella. It is currently classified as a "subspecies group" within the fox sparrow, pending wider-spread acceptance of its species status.
Region
Western North America
Typical Environment
Breeds primarily in the montane chaparral and mixed conifer–shrub mosaics of the Sierra Nevada and adjacent ranges of California, extending locally to far western Nevada and southern Oregon. In the nonbreeding season it descends to lower elevations across California and into northern Baja California, frequenting brushy canyons, riparian thickets, and coastal scrub. It favors dense, shrubby slopes with ample leaf litter for ground foraging. Winter range can overlap with other fox sparrow groups in brushy lowlands.
Altitude Range
900–3200 m
Climate Zone
Highland
Ease of Keeping
Beginner friendly: 1/5
The Thick-billed Fox Sparrow is the large-billed Sierra Nevada member of the fox sparrow complex, often split as its own species by some authorities. Its hefty, conical bill is well-suited to cracking hard chaparral seeds like manzanita. Birds breed in high-elevation shrubfields and move downslope in winter, often visiting brushy foothills. Taxonomy is unsettled, with some lists retaining it within a broader Fox Sparrow.
Temperament
shy and skulking
Flight Pattern
short rapid wingbeats
Social Behavior
Generally solitary or in pairs during the breeding season, defending dense shrub territories. Nests are placed low in shrubs or on the ground under cover, with both adults feeding the young. Outside the breeding season it may join loose mixed-species foraging groups in brushy habitats.
Migratory Pattern
Seasonal migrant
Song Description
A loud, rich series of clear, whistled notes delivered in musical phrases, often with sweet trills and doubled motifs. Calls include a sharp smack and thin tseep given from cover.
