Large, uncommon antbird of rainforest edge. Shy and difficult to see. Male is uniformly dark; female told by solid rufous cap and back contrasting with barred underparts. Note fierce expression and large, heavy bill. Often in pairs around old treefall gaps, forest edge, and other places with dense understory. Feeds on insects and occasionally follows army ant swarms. Female superficially similar to Fasciated Antshrike but much larger and unbarred above. Song is a slow series of whistles, similar to some calls of Black Nunbird but repeated more regularly.