Original description: Pipilo rufescens Swainson 1827
Taxonomic history in AOU/AOS Check-list
AOU 6 (1983): Rusty Sparrow, Aimophila rufescens
AOU 7 (1998): Rusty Sparrow, Aimophila rufescens
IUCN Conservation Status: Of least concern
Habitat: In the more southerly portions of its range, the Rusty Sparrow is widespread in lowland habitats; in the north it is more pronouncedly a bird of open pine and oak forests in mid-elevation canyons and slopes, on average found higher than the Rufous-crowned Sparrow, which prefers more arid, more sparsely vegetated rocky habitat.
Behavior: Like the towhees, this rather large, ground-loving sparrow can be inconspicuous when it is foraging for insects and seeds beneath vegetation. It is not usually especially furtive, however, and patience is often rewarded with close views of the birds as they scratch on the ground in pairs or small, loosely associated groups.
Rusty Sparrows fly fairly infrequently, and usually only a short distance at a time. The short wings beat quickly and, to the human eye, irregularly; the long tail is often wagged in flight, especially just before alighting.
Males sing from low perches in bushes, rarely much above the observer’s eye level; they do not usually sing from the top, but from an exposed perch within the vegetation.
Voice: Rusty Sparrows have a dry, chattering call; loud and fast, it often changes pitch or tempo in the middle, calling to mind the rattle of a distant Belted Kingfisher. Mated pairs also perform a “reunion duet,” in which one member gives a chattering vocalization while the other gives a sustained trill. There is also a hissing tzee note, which may introduce the duet.
The variable song is a cheerful phrase with a rich, chirping quality. One common form begins with a hesitant rising chirp, then continues with three or four higher-pitched, slightly slurred notes before concluding with a strongly downslurred flourish; the effect of many songs is surprisingly Dickcissel-like, though the Rusty Sparrow’s song is never as buzzy.
Detailed description and measurements drawn from standard reference works
Adult Aimophila rufescens rufescens: Tail feathers and upper tail coverts chestnut rusty. Rump, back, and scapulars dull rusty brown with sooty shaft streaks, creating short, irregular streaks. Primaries and secondaries brown, secondaries with narrow chestnut edges; tertials with conspicuous broad chestnut edges. Most greater coverts chestnut; median coverts brown with faintly darker shafts. Nape grayish brown.
Undertail coverts and vent brownish buffy. Belly and breast dull pale buffy, flanks and sides of breast browner. Throat pale buffy whitish, separated from narrow buffy whitish jaw stripe by broad black lateral stripe, subtly and evenly tapering from bottom of throat to base of bill. Crown chestnut, with narrow gray-brown median stripe and fine black lateral stripes. Ear coverts grayish brown, bordered below by buffy whitish jaw stripe and above by well-defined black eye line. Supercilium grayish brown towards nape, narrowing and brightening to white ahead of eye and above lore. Lore broadly black. Narrow white eye ring, broken at rear by black eye line, less conspicuous at front of eye and variably obscured by black of lore, in many individuals creating a squinting mask.
Heavy bill dark blue-gray above, paler bluish below. Large, coarse tarsi and toes pinkish brown.
Juvenile Aimophila rufescens rufescens: Tail feathers and upper tail coverts chestnut rusty with darker edges. Rump, back, and scapulars dull rusty brown with sooty shaft streaks, creating short, irregular streaks. Primaries and secondaries brown with narrow chestnut edges; tertials with conspicuous broad chestnut edges. Greater and median coverts chestnut with darker shafts; median coverts with tiny yellowish tips. Nape olive brown with fine blackish streaks.
Undertail coverts and vent brownish buffy. Belly and breast dull pale buffy, flanks brownr, tending to yellowish on sides of breas; most feathers of underparts with broad, messy blackish shaft streaks. Throat pale yellow, separated from narrow yellowish white jaw stripe by broad black lateral stripe. Crown dark brown with fine blackish streaking and narrow gray-brown median stripe. Ear coverts yellowish brown, bordered below by short, fine whisker and above by smudgy black eye line. Supercilium grayish white towards nape, narrowing and brightening to yellowish ahead of eye and above lore. Lore broadly dull black. Narrow white eye ring, broken at rear by black eye line, less conspicuous at front of eye and variably obscured by black of lore.
Heavy bill dark yellow-gray above, brighter yellowish below. Large, coarse tarsi and toes pinkish brown.
Length: 170-191 mm (6.7-7.5 inches)
Wing chord 72-77 mm (2.8-3.0 inches)
Tail 67-83 mm (2.6-3.3 inches)
Mass 34 g