The Pale-tailed Barbthroat (Threnetes leucurus) is a species of hummingbird in the Trochilidae family. It is found in the Amazon Basin proper and bordering countries, Brazil, Bolivia, Colombia, Ecuador, Peru, French Guiana, Guyana, Suriname, and Venezuela. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical swamps.
The taxonomy of the Threnetes leucurus/T. niger complex has caused much confusion in recent years: Schuchmann & Hinkelmann (1999) considered the Sooty Barbthroat a melanistic variant of T. leucurus, but as it was described first, its scientific name was adopted for the entire species; Pale-tailed Barbthroat (T. niger). This, however, has not been accepted by all authorities, notably SACC, which consider both T. niger and T. leucurus as valid species.