Common Scale-backed Antbird

The common scale-backed antbird is 12 to 13 cm (4.7 to 5.1 in) long and weighs 15 to 22 g (0.53 to 0.78 oz). Adult males of the nominate subspecies W. p. poecilinotus are mostly gray; their upperparts are darker than their underparts. They have a white patch between the scapulars. Their lower back has white-edged black patches that give it its English name. Their wings and tail are black with white edges and tips on many feathers. Adult females have a reddish yellow-brown crown and face. Their upperparts are mostly olive-brown with buff-edged brownish black patches on the lower back. They also have a white patch between the scapulars. Their flight feathers are blackish brown with reddish brown edges and their tail is dark olive-brown with white spots and a blackish band near the end. Their throat is pale grayish white. Their underparts are gray with a reddish yellow-brown tinge on the flanks. Females of subspecies W. p. duidae have a black lower back and rump with wide white feather edges, a white-spotted black tail, reddish yellow-brown underparts with a cinnamon-rufous center to the belly, and olive-brown tinged flanks. Females of W. p. lepidonota are similar to those of duidae but paler and with a browner crown and a light buff center to the belly. Females of W. p. griseiventris have a rufous-buff face, a plain lower back and rump, a pale gray throat, and gray underparts. …

The subspecies of the common scale-backed antbird are found thus:

W. p. poecilinotus: central and southeastern Venezuela, the Guianas, and northeastern Brazil from Roraima to Amapá W. p. duidae: east-central Colombia, southwestern Venezuela, and northwestern Brazil along the Rio Negro W. p. lepidonota: southeastern Colombia, eastern Ecuador, and northeastern and east-central Peru W. p. griseiventris: south-central and southeastern Peru, northern Bolivia, and southwestern Amazonian Brazil between the rios Juruá and Madeira south into western Mato Grosso W. p. gutturalis: northeastern Peru and western Amazonian Brazil to the Rio Juruá The common scale-backed antbird primarily inhabits the understorey of humid terra firme evergreen forest. It also occurs in várzea and igapó forest. In elevation it reaches 1,350 m (4,400 ft) in Brazil, 1,300 m (4,300 ft) in Venezuela, and 800 m (2,600 ft) in Colombia. In Ecuador it mostly occurs below 700 m (2,300 ft) but does reach 1,100 m (3,600 ft). In Peru it occurs locally to 1,350 m (4,400 ft) but is mostly below 900 m (3,000 ft).

The common scale-backed antbird feeds mostly on a wide variety of arthropods; it has also been noted eating small lizards. It typically forages individually, in pairs, and in family groups, usually within about 1 m (3 ft) of the ground though sometimes as high as 3 m (10 ft) and rarely to 5 m (16 ft). In some parts of its range it joins mixed-species feeding flocks. It follows swarms of army ants that pass through its territory to capture prey fleeing the ants, but it just as often forages away from ant swarms. It captures prey mostly by short sallies from a perch to the ground but also to foliage, branches, and vines. It sometimes stays on the ground probing and flicking leaf litter. At ant swarms it defers to other species.