The sexes are different in feather coloration, with males having distinct brilliance and ornamentation of head, neck, wing, and breast feathers. 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). Of those species that have been measured during flying, the top flight speeds of hummingbirds exceed 15 m/s (54 km/h 34 mph). During flight, hummingbird feet are tucked up under the body, enabling optimal aerodynamics and maneuverability. 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. 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 of feathers, nest-building by females, and during fights to grab feathers of opponents. The toes of hummingbirds are formed as claws (image) with ridged inner surfaces to aid gripping onto flower stems or petals. Hummingbird legs are short with no knees, and have feet with three toes pointing forward and one backward – the hallux. Ĭlose-up of toe arrangement in a ruby-throated hummingbird foot, showing three claw-like toes forward and one backward. Hummingbirds have extremely rapid wing-beats as high as 80 per second, supported by a high metabolic rate dependent on foraging for sugars from flower nectar. In some species, the tail feathers produce sounds used by males during courtship flying.

Particularly while hovering, the wing beats produce the humming sounds, which function to alert other birds.

Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling helicopter-like flight in any direction, including the ability to hover. The bee hummingbird – only 6 centimetres (2.4 in) long and weighing about 2 grams (0.071 oz) – is the world's smallest bird and smallest warm-blooded vertebrate. They have characteristic long, narrow beaks (bills) which may be straight of varying lengths or highly curved. Morphology Īcross the estimated 366 species, hummingbird weights range from as small as 2 grams (0.071 oz) to as large as 20 grams (0.71 oz). 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. Hummingbirds are the smallest known and smallest living avian therapod dinosaurs. The common ancestor of extant hummingbirds is estimated to have lived 22 million years ago in South America. Hummingbirds split from their sister group, the swifts and treeswifts, around 42 million years ago. 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 3,900 miles (6,300 km). 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. Hummingbirds have the highest mass-specific metabolic rate of any homeothermic animal.

They hover at rapid wing-flapping rates, which vary from around 12 beats per second in the largest species to 80 per second in small hummingbirds. They are known as hummingbirds because of the humming sound created by their beating wings, which flap at high frequencies audible to other birds and humans. Noted for long beaks, hummingbirds are specialized for feeding on flower nectar, but all species also consume small insects. The smallest is the 5 cm (2.0 in) bee hummingbird, which weighs less than 2.0 g (0.07 oz), and the largest is the 23 cm (9.1 in) giant hummingbird, weighing 18–24 grams (0.63–0.85 oz). Hummingbirds are the smallest mature birds, measuring 7.5–13 cm (3–5 in) in length. Among all birds, male hummingbirds have the widest diversity of plumage color, particularly in blues, greens, and purples. 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. About 28 hummingbird species are listed as endangered or critically endangered, with numerous species declining in population. With about 366 species and 113 genera, they occur from Alaska to Tierra del Fuego, but most species are found in Central and South America. Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. For an alphabetic species list, see List of hummingbird species

Hummingbird nest