The sword-billed hummingbird (Ensifera ensifera), also known as the swordbill, is a neotropical species of hummingbird from the Andean regions of South America. It is the only member in the genus Ensifera. Among the largest species of hummingbird, it is characterized by its unusually long bill, being the only bird to have a beak longer than the rest of its body, excluding the tail. It uses its bill to drink nectar from flowers with long corollas and has coevolved with the species Passiflora mixta. While most hummingbirds preen using their bills, the sword-billed hummingbird uses its feet to scratch and preen due to its bill being so long. The sword-billed hummingbird is a trap-line feeder and feeds on nectar, especially from Passiflora mixta and other passionflowers. It also hawks for insects. It breeds from February to March and builds cup nests using moss. The sword-billed hummingbird is listed as being of least concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List, but is threatened by climate change and deforestation. Taxonomy and systematics The sword-billed hummingbird was first described as Ornismya ensifera by Auguste Boissonneau in 1839 on the basis of specimens from Santa Fé, Bogotá, Colombia. It was moved to the genus Ensifera in 1843 by René Lesson. The generic and specific name ensifera is derived from the Latin words ensis (sword) and ferre (to carry) and means sword-wielder, referring to the species' large beak. Sword-billed hummingbird is the official common name designated by the International Ornithologists' Union. Other common names for the species include sword billed hummingbird, swordbill, and swordbill hummingbird. The sword-billed hummingbird is the only species in the genus Ensifera. In 1939, Ensifera ensifera caerulescens was described as a subspecies by Willoughby Lowe on the basis of a specimen from the Royal Albert Memorial Museum. However, it has since been lumped with the nominate subspecies as it is likely that the specimen had either aberrant plumage or was discolored. The species is now considered monotypic. Description The sword-billed hummingbird is among the largest species of hummingbirds. Adults are long excluding the bill and weigh , with males being slightly larger on average than females. The most distinctive feature of the species is the enormous bill, which is long. The bill is the largest of any hummingbird and the largest with respect to body length for any bird. The sword-billed hummingbird displays