Common Scale-backed Antbird is a medium-sized, short-tailed antbird of the understory of humid lowland forest. This species is common and widespread throughout Amazonia, except for eastern Brazil south of the Amazon, where it is replaced by its sister species, Xingu Scale-backed Antbird (X. vidua). The head, upper back, and underparts of the male all are pale gray; the lower back is black, each feather with a broad white tip, forming the "scaled" pattern. The wings and tail also are black and white; in one subspecies, the throat and upper breast are black as well. Geographic variation is more extreme in the case of the female: across the five subspecies, the back of the female may be scaled like the male or uniformly brown, and the underparts may be buffy brown or gray. Common Scale-backed Antbird is not an obligate follower of army ants, but it regularly attends these swarms, where it feeds on insects and small vertebrates that are attempting to escape the ants.