Rufous-gaped Hillstar is a large, dark colored, long-billed hummingbird of the northern Andes. Both sexes are dark coppery green above, with a blue throat and breast and a gray belly. The English name "Rufous-gaped" refers to the conspicuous rufous submoustachial stripe. The tail also is extensively white, although the central and outermost pairs of rectrices are dark. The two species of Urochroa hillstars are not closely related to the Oreotrochilus hillstars, and also differ in habitat preferences: species of Oreotrochilus occupy puna and paramo grasslands above tree line, whereas Rufous-gaped and White-tailed (Urochroa leucura) hillstars occur in humid forest on the lower slopes of the Andes. Rufous-gaped Hillstar is not well known, although it is locally common. Rufous-gaped Hillstar forages on nectar and aerial insects in the under- and midstory of humid montane forest edge and forest clearings, often near water.