Sharp-billed Canastero

The sharp-billed canastero is 14 to 15 cm (5.5 to 5.9 in) long and weighs 12 to 14 g (0.42 to 0.49 oz). It is one of the smaller canasteros, with a pointed bill that is thinner than those of most others. The sexes have the same plumage. Adults of the nominate subspecies have a gray-brown face with a paler supercilium. Their crown is dull brown, their back and rump a slightly paler brown, and their uppertail coverts long and browner. Their wings are mostly dull rufescent brown. Their central pair of tail feathers are pointed; they and the next two pairs are dark fuscous brown with dusky tips and the rest mostly dull rufous with dark inner webs. Their chin and upper throat are rufous to tawny with dark-tipped pale streaks. Their lower throat and breast are pale grayish brown with faint streaks on the latter, their belly pale buff-brown, and their flanks and undertail coverts darker buff-brown with a rufescent tinge. Their iris is brown, their maxilla slate-gray to black, their mandible gray-horn, and their legs and feet slate-gray. Juveniles do not have the throat patch and their breast is mottled. Subspecies A. p. sordida differs from the nominate only by having entirely rufous outer tail feathers.

The nominate subspecies of the sharp-billed canastero breeds in central and southern Argentina and winters to northern Argentina and southern Paraguay and Uruguay. Subspecies A. p. sordida breeds in central and southern Chile and west-central Argentina and winters to northern Argentina and southern Bolivia. The species inhabits a variety of semi-arid to arid landscapes including shrub-steppe, lowland and montane scrublands, and temperate, hilly, and rocky grasslands. In the non-breeding season it also occurs in tall grass, marshy areas, and Gran Chaco scrub. In elevation it mostly ranges from sea level to 2,000 m (6,600 ft) but locally occurs as high as 3,000 m (9,800 ft).

The sharp-billed canastero feeds on arthropods. It usually forages singly or in pairs, gleaning prey from foliage and only rarely on the ground.