Rare antbird nearly endemic to the lowlands of eastern Ecuador. It was recently found in neighboring Colombia, and is likely to occur over the border in Peru as well. Male is pure black. Female is chestnut with a black hood. Both sexes are very similar to White-shouldered Antbird, but lack blue markings around the eye. Male also similar to male White-shouldered Antshrike, but lacks white wing markings and lives in different habitat. Cocha Antshrike is usually encountered in pairs that skulk low in swampy forest along the edge of ponds and sluggish creeks. Typical song is a fast, monotonous series of clucks.