Unique and spectacular hummingbird of the upper humid montane forest in Bolivia. Plumage mostly black, with striking white feathers on breast and a shining blue rump. Occurs to, and sometimes just above, treeline on the east side of the Andes from western Santa Cruz department to La Paz. The only black hummingbird in its range. This species is generally patchily distributed, but can be locally common, especially where flowers are abundant.