Crag Chilia

The crag chilia is 18 to 19 cm (7.1 to 7.5 in) long and weighs 31 to 40 g (1.1 to 1.4 oz). Adults of the nominate subspecies O. m. melanurus have a narrow whitish supercilium, dark brown lores and auriculars, and whitish cheeks. Their upperparts are mostly darkish brown with a rufous rump and uppertail coverts. Their tail is mostly blackish brown with some rufous at the base and outer web of the outermost pair of feathers. Their upperwing coverts are dusky brown and their wings are darkish brown with a wide rufous band. Their throat is whitish, their breast dull smoky grayish, their belly dull brown, and their flanks and undertail coverts rufous. Their iris is brown, their maxilla blackish, their mandible pale gray with a blackish tip, and their legs and feet blackish. Juveniles have pale edges on their back feathers and faint barring on their underparts. Subspecies O. m. atacamae is paler and sandier than the nominate. Its supercilium is whiter and more distinct. Its upperwing coverts are grayish brown, its breast pale grayish with white streaks, and its flanks pale brown. Its bill is shorter and narrower.

The crag chilia is endemic to north-central and central Chile. Subspecies O. m. atacamae is found from Huasco Province in the Atacama Region to the Coquimbo Region. O. m. melanurus is found further south, between San Felipe de Aconcagua Province in the Valparaíso Region and Colchagua Province in the O'Higgins Region. The crag chilia inhabits arid scrublands with shrubby rock hillsides and cliffs with sparse vegetation. There is no consensus on its elevational range. In the non-breeding season it occurs as low as sea level. In the breeding season, different authors place its upper limit between 2,200 and 3,000 m (7,200 and 9,800 ft).

The crag chilia's diet is predominantly arthropods such as Orthoptera and Lepidoptera but also includes seeds and fruits such as those of Tristerix species and Ephedra chilensis. It is usually a solitary forager that gleans from rocks and bushes and also probes crevices.