The Rufous-tailed Hummingbird is a medium-sized hummingbird endemic to the American tropics, stretching from east-central Mexico through Central America, down to Colombia, Ecuador, and Venezuela​​. Its genus, Amazilia, is named after an Inca heroine, and the species' epithet tzacatl is derived from Aztec mythology, referring to a warrior chief​​. With five recognized subspecies, this bird exhibits sexual dimorphism, as the males sport a green head and upperparts with a chestnut-brown tail, while the females have a paler gray lower breast​​​​. The species is known for its melodic "varied, high, thin, squeaky chirping" and is classified as "Least Concern" by the IUCN​​. Photographed in the Sierra Nevada de Santa Marta, Colombia.