Rusty Sparrow

The rusty sparrow is 16.5 to 20 cm (6.5 to 7.9 in) long and weighs 34 to 48 g (1.2 to 1.7 oz). The sexes have the same plumage. Adults of the nominate subspecies A. r. rufescens have a chestnut crown with black streaks and a thin olive gray or buffy stripe in its middle. They have dark brown lores, a whitish streak above the lores, a white eye-ring, and a dusky stripe behind the eye on an otherwise olive grayish face. Their back and scapulars are brown with wide black streaks. Their wings are mostly brown with chestnut secondaries and inner greater coverts. Their tail is chestnut brown. Their chin, throat, and belly are grayish buff with a blackish stripe on the side of the throat. Their flanks are a deeper brownish. Juveniles are overall duller and buffier than adults. Their crown is brown with black streaks, their upperparts are dense with thin dark brown streaks, and their lower throat, breast, and flanks have a pale yellowish wash and thin dark brown streaks. The other subspecies of the rusty sparrow differ from the nominate and each other thus:

A. r. mcleodii: less chestnut on crown, thinner streak behind the eye, and grayer upperparts than nominate A. r. antonensis: much like mcleodii but paler and grayer sides, flanks, and undertail coverts A. r. pyrgitoides: much like nominate A. r. discolor: paler overall than nominate A. r. …

The rusty sparrow has a disjunct distribution; some subspecies have very limited ranges. The subspecies are found thus:

A. r. antonensis: Sierra de San Antonio in northwestern Mexico's north-central Sonora A. r. mcleodii: northwestern Mexico from eastern Sonora and western Chihuahua south to northern Sinaloa and northwestern Durango A. r. rufescens: western and southern Mexico from southern Sinaloa south to southwestern Chiapas and east to Guanajuato to southern Puebla. A. r. pyrgitoides: eastern and southeastern Mexico from southern Tamaulipas and eastern San Luis Potosí south through Guatemala, Honduras and northern and eastern El Salvador into northwestern Nicaragua A. r. discolor: far eastern Honduras and northeastern Nicaragua A. r. pectoralis: west of pyrgitoides from Chiapas south through Guatemala into El Salvador and Honduras A. r. hypaethra: Pacific slope of northwestern Costa Rica's Cordillera de Guanacaste The rusty sparrow inhabits pine-oak forest, the edges and shrubby clearings of deciduous forest, scrublands and scrubby secondary forest, and pine savanna in the tropical to lower temperate zones. In Costa Rica it is "confined to grassy slopes dotted with boulders, dense shrubs, and small trees". Overall it ranges in elevation from sea level to 2,700 m (8,900 ft). It reaches 2,600 m (8,500 ft) in northern Central America but is rare there below 300 m (1,000 ft). …

The rusty sparrow's diet has not been studied but in Costa Rica is known to include seeds and small invertebrates. Overall it is thought to feed on seeds, insects, spiders, fruits and sometimes nectar. It feeds on the ground, usually singly or in pairs.