†Eurotrochilus
Florisuginae
Phaethornithinae
Polytminae
Lesbiinae
Patagoninae
Trochilinae
For an alphabetic species list, see List of hummingbird species
Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera,[1] they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics. They are small birds, with most species measuring 7.5–13 cm (3–5 in) in length. The smallest extant hummingbird species is the 5 cm (2.0 in) bee hummingbird, which weighs less than 2.0 g (0.07 oz). The largest hummingbird species is the 23 cm (9.1 in) giant hummingbird, weighing 18–24 grams (0.63–0.85 oz). They are specialized for feeding on flower nectar, but all species also consume flying insects or spiders.
Hummingbirds split from their sister group, the swifts and treeswifts, around 42 million years ago. The common ancestor of extant hummingbirds is estimated to have lived 22 million years ago in South America. They are known as hummingbirds because of the humming sound created by their beating wings, which flap at high frequencies audible to humans. They hover in mid-air at rapid wing-flapping rates, which vary from around 12 beats per second in the largest species to around 80 per second in small hummingbirds. Of those species that have been measured during flying in wind tunnels, their top speeds exceed 15 m/s (54 km/h; 34 mph). During courtship, some male species dive from 30 metres (100 ft) of height above a female at speeds around 23 m/s (83 km/h; 51 mph).[2][3]
Hummingbirds have the highest mass-specific metabolic rate of any homeothermic animal.[4] To conserve energy when food is scarce and at night when not foraging, they can enter torpor, a state similar to hibernation, and slow their metabolic rate to 1/15 of its normal rate.[5]
The family Trochilidae was introduced in 1825 by Irish zoologist Nicholas Aylward Vigors with Trochilus as the type genus.[6][7] Molecular phylogenetic studies of the hummingbirds have shown that the family is composed of nine major clades.[8][9] When Edward Dickinson and James Van Remsen Jr. updated the Howard and Moore Complete Checklist of the Birds of the World for the 4th edition in 2013, they divided the hummingbirds into six subfamilies.[10]
The above cladogram of the hummingbird family is based on a molecular phylogenetic study by Jimmy McGuire and collaborators published in 2014.[9] The English names are those introduced by Robert Bleiweiss, John Kirsch, and Juan Matheus in 1997.[11] The Latin names are those proposed by Dickinson and Remsen in 2013.[10]