Xingu Scale-backed Antbird

The Xingu scale-backed antbird is 12 to 13 cm (4.7 to 5.1 in) long and weighs 14 to 19.5 g (0.49 to 0.69 oz). Adult males of the nominate subspecies 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 warm brown crown and a gray face. Their upperparts are warm brown and their underparts are gray. Their throat is white. Both sexes have a grayish iris, a black bill, and pale gray legs and feet. Males of subspecies W. v. nigrigula have a black throat and slightly darker upperparts than the nominate. Females of nigrigula have a larger white patch between the scapulars than the nominate but are otherwise identical.

The Xingu scale-backed antbird is found in south-central and eastern Amazonian Brazil south of the Amazon River. The nominate subspecies occurs between the Rio Xingu and western Maranhão state and south into northern Tocantins state. Subspecies W. v. nigrigula occurs further west, between the rios Tapajós and Xingu and south into northern Mato Grosso state. The species primarily inhabits the understorey of humid terra firme evergreen forest and also occurs in várzea forest. In elevation it ranges from sea level to 800 m (2,600 ft).

The Xingu scale-backed antbird feeds mostly on a wide variety of arthropods. 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). 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.