Ruby-Throated Hummingbird (Archilochus colubris): Facts

Appearance

The ruby-throated hummingbird is a tiny, slim bird with a straight, needle-like black bill about 2 cm (0.8 in) long. Both sexes have shining metallic-green backs and crowns, grayish-white underparts and dark wings that look almost black.

Adult males wear the famous gorget, a throat patch of iridescent ruby-red feathers bordered with velvety black at the top. The color comes from the structure of the feathers, which reflects light like a soap bubble, so the throat blazes red when the bird faces the sun and looks dull black when it turns. Males also have a forked black tail and slightly greenish flanks.

Females have a white throat, sometimes with faint dusky streaks, and a rounded tail with white tips on the outer feathers. Young males look like females in their first fall, often with heavier streaking on the throat, and grow their first red feathers during the winter molt in the tropics.

Like all hummingbirds, ruby-throats have very short legs and small feet with three toes forward and one back. They can perch and grip well but cannot walk or hop; to move along a branch they shuffle sideways or simply fly.

How big is a ruby-throated hummingbird?

This is one of the smallest birds in North America. Females are slightly larger and heavier than males, which is unusual among birds but typical of many hummingbirds.

The heaviest birds are those that have fattened up before migration, when a hummingbird can nearly double its normal body weight. Even then it weighs only about 5–6 g (0.2 oz). For the tiniest bird of all, see what is the smallest bird in the world?

Habitat and range

Ruby-throated hummingbirds breed across eastern North America, roughly east of the Great Plains, from southern Canada (Alberta and Saskatchewan east to Nova Scotia) south to Florida and the Gulf Coast. It has the largest breeding range of any hummingbird in the United States, and throughout most of the East it is the only hummingbird you will see in summer.

They live in deciduous and mixed pine forests, along woodland edges and streams, and in orchards, parks and suburban gardens with flowering plants. They need trees for nesting and perching and a steady supply of nectar-rich flowers.

In winter they move to southern Mexico and Central America, as far south as western Panama, with smaller numbers in southern Florida, along the Gulf Coast and in the Caribbean. The full story is in where do hummingbirds go in winter?

Diet and feeding

Ruby-throated hummingbirds are often thought of as nectar drinkers, but they are really omnivores. Sugary nectar fuels their flight, while insects and spiders supply the protein, fats, vitamins and minerals that nectar lacks.

They favor red, orange and pink tubular flowers such as trumpet creeper, cardinal flower, bee balm, coral honeysuckle, columbine and jewelweed. The bird pushes its bill deep into the flower and laps nectar with a long, forked tongue, picking up pollen on its head and bill and carrying it to the next flower. This makes it an important pollinator of many native plants.

Insects are caught in midair, picked from leaves and bark or taken from spider webs, and include gnats, mosquitoes, small flies, aphids and tiny spiders. In early spring, before many flowers open, ruby-throats often follow yellow-bellied sapsuckers, woodpeckers that drill rows of holes in trees, and drink the sugary sap that oozes from the wells. More detail is in what do hummingbirds eat?

Flight and metabolism

Hummingbirds are the only birds that can hover for long periods and fly backward. Their wings attach to the body mainly at a flexible shoulder joint, so the whole wing works like a rigid paddle that twists almost upside down on each stroke. Hovering ruby-throats beat their wings about 50–55 times per second, a little more in fast maneuvers.

Their flight muscles make up roughly a quarter to a third of their body weight. To power them, hummingbirds have one of the highest metabolic rates of any animal: a ruby-throat’s heart can beat more than 1,200 times a minute, and it breathes around 250 times a minute even at rest. In level flight it travels at around 40–50 km/h (25–30 mph), and males dive even faster in courtship.

Such a fast-running body burns energy quickly, so these birds feed every few minutes through the day. On cold nights they can save energy by dropping into torpor, a deep, sleep-like state in which body temperature and heart rate fall sharply.

Behavior and territories

Ruby-throated hummingbirds are solitary and famously feisty. Males and females alike defend good patches of flowers or feeders, chasing intruders with angry, squeaky chips and buzzing dives. Even much larger birds and large insects can be chased away.

Their calls are high, sharp chips and twitters. They do not sing a real song; much of the “humming” you hear comes from the wings themselves. A male’s wings make a higher-pitched buzz than a female’s, and in courtship he adds clicking and whining sounds made by his wing and tail feathers.

Reproduction and life cycle

Males arrive on the breeding grounds in spring a few days to weeks before females and set up territories. When a female enters, the male performs a dramatic U-shaped dive display, swooping down and up in arcs several meters across, and then a fast side-to-side “shuttle” flight in front of her. The pair does not stay together: after mating the male leaves, and he may mate with several females.

The female alone builds a tiny cup nest, usually 3–12 m (10–40 ft) up on a small, downward-sloping branch of a deciduous tree. She weaves it from bud scales and soft plant down, binds it with spider silk so it can stretch as the chicks grow, and covers the outside with flakes of lichen for camouflage.

She lays 1–3 white eggs, usually two, each about the size of a navy bean, and incubates them for about 12–14 days. The chicks hatch blind and almost naked. The mother feeds them by pushing her bill into their throats and regurgitating a mix of nectar and insects, and they leave the nest at about 18–22 days old. A female can raise one or two broods each summer.

Lifespan

Most ruby-throated hummingbirds live only a few years. Many die in their first year, especially during their first migration, but adults that survive commonly live 3–5 years. The oldest known wild ruby-throat was a banded female at least 9 years and 1 month old. Females tend to outlive males, which rarely survive beyond about 5 years, probably because territory defense and courtship use up so much energy. See how long do hummingbirds live? for records of other species.

Predators and threats

Few predators are quick enough to catch a free-flying adult hummingbird, but they are vulnerable when perched, feeding or nesting. Known predators include small, agile hawks and falcons such as sharp-shinned hawks, merlins and American kestrels, as well as loggerhead shrikes and domestic cats. Large praying mantises, big orb-weaving spiders and even green darner dragonflies have been recorded catching hummingbirds. Blue jays, squirrels, chipmunks and snakes raid nests.

Human-related threats include collisions with windows, loss of forests and flowering plants, pesticides that reduce insect prey, and the long journeys between breeding and wintering grounds. Severe weather during migration, such as storms over the Gulf of Mexico, can also kill many birds.

Conservation status

The IUCN Red List classifies the ruby-throated hummingbird as Least Concern. Partners in Flight estimates a population of around 34–36 million birds, and breeding numbers grew for several decades after 1970, helped by gardens and feeders. Some recent counts suggest a modest decline, so ornithologists continue to monitor the species. It is protected in the United States and Canada under migratory bird laws, which means the birds, their nests and eggs may not be taken or disturbed.

Myths and facts

Myth: Hummingbirds migrate by riding on the backs of geese. There is no evidence for this. Geese and hummingbirds migrate at different times and on different routes, and hummingbirds make the entire journey on their own wings.

Myth: Hummingbirds never land. They perch often, to rest, preen and watch over their territory, and spend much of the day sitting still. What they cannot do is walk.

Fact: Their eggs are among the smallest of any bird. A ruby-throat’s egg is barely 13 mm (0.5 in) long, and the whole nest is about the size of a walnut shell. To learn how these birds handle cold nights, read how do hummingbirds sleep?