Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With approximately 375 species and 113 genera, they occur from Alaska to Tierra del Fuego, but most species are found in Central and South America. As of 2026, 21 hummingbird species are listed as endangered or critically endangered, with about 255 species declining in population.
Hummingbirds have varied specialized characteristics to enable rapid, maneuverable flight: exceptional metabolic capacity, adaptations to high altitude, sensitive visual and communication abilities, and long-distance migration in some species. Among all birds, male hummingbirds have the widest diversity of plumage color, particularly in blues, greens, and purples. Hummingbirds are the smallest mature birds, measuring in length. The smallest is the bee hummingbird, which weighs less than , and the largest is the giant hummingbird, weighing . Noted for long beaks, hummingbirds are specialized for feeding on flower nectar, but all species also consume small insects.
Hummingbirds are known by that name because of the humming sound created by their beating wings, which flap at high frequencies audible to other birds and humans. They hover at rapid wing-flapping rates, which vary from around 12 beats per second in the largest species to 99 per second in small hummingbirds.
Hummingbirds have the highest mass-specific metabolic rate of any homeothermic animal. 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 of its normal rate. While most hummingbirds do not migrate, the rufous hummingbird has one of the longest migrations among birds, traveling twice per year between Alaska and Mexico, a distance of about .
Hummingbirds split from their sister group, the swifts and treeswifts, around 42 million years ago. The oldest known fossil hummingbird is Eurotrochilus, from the Rupelian Stage of Early Oligocene Europe.
Description
Hummingbirds are the smallest known and smallest living avian theropod dinosaurs. The iridescent colors and highly specialized feathers of many species (mainly in males) give some hummingbirds exotic common names, such as sun gem, fairy, woodstar, sapphire or sylph.
Morphology Across the estimated 375 species, hummingbird weights range from as small as to as large as . They have characteristic long, narrow beaks (bills) which may be straight (of varying lengths) or highly curved. The bee hummingbird only long and weighing about is the world's smallest bird and smallest warm-blooded vertebrate. The giant hummingbird is the largest, having a mass of – approximately twice as heavy as the next largest hummingbird – with a wingspan of and body length of .
Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling helicopter-like flight in any direction, including the ability to hover. Particularly while hovering, the wing beats produce the humming sounds, which function to alert other birds. In some species, the tail feathers produce sounds used by males during courtship flying. One species of hummingbird – the little woodstar (Chaetocercus bombus) – has a wing-beat frequency of 99 per second during hovering. Such extreme flight demands are supported by a high metabolic rate dependent on foraging for sugars from flower nectar.
Hummingbird legs are short with feet having three toes pointing forward and one backward the hallux. The toes of hummingbirds are formed as claws with ridged inner surfaces to aid gripping onto flower stems or petals. Hummingbirds do not walk on the ground or hop like most birds, but rather shuffle laterally and use their feet to grip while perching, preening feathers, or nest-building (by females), and during fights to grab feathers of opponents.
Hummingbirds apply their legs as pistons for generating thrust upon taking flight, although the shortness of their legs provides about 20% less propulsion than assessed in other birds. During flight, hummingbird feet are tucked up under the body, enabling optimal aerodynamics and maneuverability.
Of those species that have been measured during flight, the top flight speeds of hummingbirds exceed . During courtship, some male species dive from of height above a female at speeds around .
The sexes differ in feather coloration, with males having distinct brilliance and ornamentation of head, neck, wing, and breast feathers. The most typical feather ornament in males is the gorget a bib-like iridescent neck-feather patch that changes brilliance with the viewing angle to attract females and warn male competitors away from territory.
Life cycle Hummingbirds begin mating when they are a year old. Sex occurs over 3–5 seconds when the male joins its cloaca with the female's, passing sperm to fertilize the female's eggs.
Hummingbird females build a nest resembling a small cup about in diameter, commonly attached to a tree branch using spider webs, lichens, moss, and loose strings of plant fibers (image). Typically, two pea-sized white eggs (image) the smallest of any bird are incubated over 2–3 weeks in breeding season. Fed by regurgitation only from the mother, the chicks fledge about 3 weeks after hatching.
As the nestlings develop juvenile plumage, they do more and more wing flapping as they develop their ability to fly. The nestlings finally leave the nest (fledge), but are initially awkward fliers still fed by their mother.
Nectar-feeding hummingbirds ingest large volumes of liquid which must be eliminated. Nestlings elevate their cloaca ejecting a stream of dilute liquid containing suspended fecal material beyond the rim of the nest.
The average lifespan of a ruby-throated hummingbird is estimated to be 3–5 years, with most deaths occurring in yearlings, although one banded ruby-throated hummingbird lived for 9 years and 2 months. Bee hummingbirds live 7–10 years.
Population estimates and threatened species Although most hummingbird species live in remote habitats where their population numbers are difficult to assess, population studies in the United States and Canada indicate that the ruby-throated hummingbird numbers are around 34 million, rufous hummingbirds are around 19 million, black-chinned, Anna's, and broad-tailed hummingbirds are about 8 million each, calliopes at 4 million, and Costa's and Allen's hummingbirds are around 2 million each. Several species exist only in the thousands or hundreds.
According to the International Union for Conservation of Nature Red List of Threatened Species in 2026, 8 hummingbird species are classified as critically endangered, 13 are endangered, 13 are vulnerable, and 22 species are near-threatened. Two species the Brace's emerald (Riccordia bracei) and Caribbean emerald (Riccordia elegans) have been declared extinct. Although 316 species are considered to be of least concern, 255 species are declining in population numbers, with only 87 species rated as stable and 8 increasing in numbers.
Of the 15 species of North American hummingbirds that inhabit the United States and Canada, several have changed their range of distribution, while others showed declines in numbers since the 1970s, including in 2023 with dozens of hummingbird species in decline. As of the 21st century, rufous, Costa's, calliope, broad-tailed, and Allen's hummingbirds are in significant decline, some losing as much as 67% of their numbers since 1970 at nearly double the rate of population loss over the previous 50 years. The ruby-throated hummingbird population the most populous North American hummingbird decreased by 17% over the early 21st century. Habitat loss, glass collisions, cat predation, pesticides, and possibly climate change affecting food availability, migration signals, and breeding are factors that may contribute to declining hummingbird numbers. By contrast, Anna's hummingbirds had large population growth at an accelerating rate since 2010, and expanded their range northward to reside year-round in cold winter climates.
Superficially similar species Some species of sunbirds – an Old World group restricted in distribution to Eurasia, Africa, and Australia – resemble hummingbirds in appearance and behavior, but are not related to hummingbirds, as their resemblance is due to convergent evolution.
The hummingbird moth has flying and feeding characteristics similar to those of a hummingbird. Hummingbirds may be mistaken for hummingbird hawk-moths, which are large, flying insects with hovering capabilities, and exist only in Eurasia.
Range
Hummingbirds are restricted to the Americas from south central Alaska to Tierra del Fuego, including the Caribbean. The majority of species occur in tropical and subtropical Central and South America, but several species also breed in temperate climates and some hillstars occur even in alpine Andean highlands at altitudes up to .
The greatest species richness is in humid tropical and subtropical forests of the northern Andes and adjacent foothills, but the number of species found in the Atlantic Forest, Central America or southern Mexico also far exceeds the number found in southern South America, the Caribbean islands, the United States, and Canada. While fewer than 25 different species of hummingbirds have been recorded from the United States and fewer than 10 from Canada and Chile each, Colombia alone has more than 160 and the comparably small Ecuador has about 130 species.
Taxonomy and systematics
The family Trochilidae was introduced in 1825 by Irish zoologist Nicholas Aylward Vigors with Trochilus as the type genus. In traditional taxonomy, hummingbirds are placed in the order Apodiformes, which also contains the swifts, but some taxonomists have separated them into their own order, the Trochiliformes.
Hummingbird wing bones are hollow and fragile, making fossilization difficult and leaving their evolutionary history poorly documented. Though scientists theorize that hummingbirds originated in South America, where species diversity is greatest, possible ancestors of extant hummingbirds may have lived in parts of Europe and what is southern Russia today.
As of 2025, 375 hummingbird species have been identified. They have been traditionally divided into two subfamilies: the hermits (Phaethornithinae) and the typical hummingbirds (Trochilinae, including all the other species). Molecular phylogenetic studies have shown, though, that the hermits are sister to the topazes and jacobins, making the former definition of Trochilinae not monophyletic. The hummingbirds form nine major clades: the topazes and jacobins, the hermits, the mangoes, the coquettes, the brilliants, the giant hummingbird (Patagona gigas), the mountaingems, the bees, and the emeralds. The topazes and jacobins combined have the oldest split with the rest of the hummingbirds. The hummingbird family has the third-greatest number of species of any bird family (after the tyrant flycatchers and the tanagers).
Fossil hummingbirds are known from the Pleistocene of Brazil and the Bahamas, but neither has yet been scientifically described, and fossils and subfossils of a few extant species are known. Until recently, older fossils had not been securely identifiable as those of hummingbirds.
In 2004, Gerald Mayr identified two 30-million-year-old hummingbird fossils. The fossils of this primitive hummingbird species, named Eurotrochilus inexpectatus ("unexpected European hummingbird"), had been sitting in a museum drawer in Stuttgart; they had been unearthed in a clay pit at Wiesloch–Frauenweiler, south of Heidelberg, Germany, and, because hummingbirds were assumed to have never occurred outside the Americas, were not recognized to be hummingbirds until Mayr took a closer look at them.