This tiny hummingbird occurs from central and southern Bolivia to northwestern Argentina along the eastern Andes. The male is notable for its slender, elongated tail.
At about 7–8 cm, it is a very small hummingbird, and the sexes differ in plumage. The male has slender, elongated tail feathers; the female has pale rufous underparts.
It uses eastern-Andean woodland, forest edges, and scrub. It builds a cup nest on a branch with lichens and spider silk, usually laying two eggs.
An extinction-risk assessment has not been added yet.