Rather long-tailed antbird of humid forest understory in lowlands and mountains from Colombia to Bolivia. Usually stays hidden in dense vegetation and thickets, sometimes attending army antswarms. Male is black; female is extremely variable throughout range. On the west slope of the Andes in Ecuador and extreme northwestern Peru, female is plain brownish with no distinctive features. On the east slope of the Andes from Colombia to northern Peru, female has black body and rufous-brown upperparts. In central Peru, female is entirely rufous-brown with a black head. From southeast Peru to Bolivia, female is rufous-brown overall with a tawny chest and a distinctive pale eyebrow. Both sexes have ruby-red eyes and a white patch on the back that is usually hidden; it is exposed when the bird is excited such as when defending its territory. Song is a very fast series of short whistles.