Trochilus colubris Linnaeus, 1758 The ruby-throated hummingbird (Archilochus colubris) is a species of hummingbird that generally spends the winter in Central America, Mexico, and Florida, and migrates to Canada and other parts of Eastern North America for the summer to breed.

The ruby-throated hummingbird was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Trochilus colubris.

[12][13] The toes are formed as claws (image) with ridged inner surfaces to aid gripping onto flower stems or petals.

[1][18] Despite substantial population growth from 1970 through the early 21st century, numbers of ruby-throated birds declined by 17% over the census reported in 2021.

A second, rather faint, repeated whining sound is sometimes produced with the outer tail-feathers during the dive, as the male flies over the female, spreading and shutting the tail as he does so.

[10] The ruby-throated hummingbird is migratory, spending most of the winter in Florida, southern Mexico and Central America,[21] as far south as extreme western Panama,[22] and the West Indies.

[21] This feat is impressive, as an 800 km (500 mi), non-stop flight over water would seemingly require a caloric energy that far exceeds an adult hummingbird's body weight of 3 g (0.11 oz).

[26] During flight, hummingbird oxygen consumption per gram of muscle tissue is approximately 10 times higher than that seen for elite human athletes.

Hummingbirds have a relatively short humerus with proportionally massive deltoid-pectoral muscles which permit pronounced wing supination during upstroke when hovering.

[28] A hummingbird's ability to hover is due to its small mass, high wingbeat frequency and relatively large margin of mass-specific power available for flight.

Several anatomical features contribute further, including proportionally massive major flight muscles (pectoralis major and supracoracoideus) and wing anatomy that enables the bird to leave its wings extended yet turned over (supine) during the upstroke.

[29][30] Hummingbirds and insects gain lift during hovering partially through inversion of their cambered wings during an upstroke.

They do not form breeding pairs, with males departing immediately after the reproductive act and females providing all parental care.

If the female perches, the male begins flying in very rapid horizontal arcs less than 0.5 m (1.6 ft) in front of her.

If the female is receptive to the male, she may give a call and assume a solicitous posture with her tail feathers cocked and her wings drooped.

[10] The nest is composed of bud scales, with lichen on the exterior, bound with spider's silk, and lined with fibers such as plant down (often dandelion or thistle down) and animal hair.

Due to their small size, hummingbirds are vulnerable even to passerine birds and other animals which generally feed on insects.

Chief among their predators are the smaller, swifter raptors like sharp-shinned hawks, merlins, American kestrels and Mississippi kites as well as domestic cats, loggerhead shrikes and even greater roadrunners, all of which are likely to ambush the hummingbird while it sits or sleeps on a perch or are distracted by breeding or foraging activities.

Blue jays are common predators of nests, as are several other corvids in addition to some icterids, bats, squirrels and chipmunks.