The Esmeraldas Antbird (Myrmeciza nigricauda) is a species of bird in the Thamnophilidae family. It is found in Colombia and Ecuador. The species has been the source of taxonomic confusion in the past, as the male was placed as a separate species (and in another genus, Sipia). It is only recently that the male and female were realised to be the same species.
Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montanes.