Archilochus Colubris

One of this bird's most remarkable feats is doubling its body weight before flying nonstop across the Gulf of Mexico, a journey of roughly 900 miles that some individuals complete in about 20 hours without stopping to feed or drink.

The Archilochus colubris is a tiny hummingbird of the family Trochilidae, native to eastern North America. It winters across Central America, Mexico, and Florida before migrating north each spring to breed as far as southern Canada. The IUCN lists it as Least Concern, and it remains the most common hummingbird species in the eastern half of the continent.

With an estimated 35 million individuals recorded in 2021, it is easy to spot yet endlessly interesting: a bird whose hovering flight, ruby throat, and long-distance migration continue to draw birdwatchers and researchers alike.

The clearest way to identify an adult male is its iridescent ruby-red throat patch, or gorget, bordered by a narrow band of velvety black — though the red flash is highly directional and can look dull black from many angles. Females lack this gorget entirely, showing a plain or lightly streaked white throat instead.

This is a tiny bird, measuring 7 to 9 cm (2.8 to 3.5 in) long with a wingspan of 8 to 11 cm (3.1 to 4.3 in). Weight ranges from 2 to 6 g, averaging 3.4 g in males versus a slightly heavier 3.8 g in females. Its bill is long, straight, and slender, reaching up to 2 cm.

Both sexes are metallic green above and grayish white below, with near-black wings. The male's tail is forked with a faint violet sheen, while the female's tail is notched, with outer feathers banded in green, black, and white. Juvenile males resemble adult females but usually carry heavier throat markings.

Legs are short, ending in three forward-pointing toes and one backward-pointing hallux, each tipped with a ridged claw for gripping flower stems and petals; the middle toe measures about 0.6 cm. These birds can only shuffle along a branch rather than walk, though they can scratch-preen with their feet. A full molt takes place once a year on the wintering grounds, beginning in early fall and finishing by late winter.

The ruby-throated hummingbird breeds throughout most of the eastern United States and south-central to southeastern Canada, particularly Ontario, using deciduous and pine forests, forest edges, orchards, and gardens; among hummingbirds recorded in the United States, it has the largest breeding range.

In winter, most of the population moves to Florida, southern Mexico, and Central America as far south as extreme western Panama, plus the West Indies, occupying tropical deciduous forest, citrus groves, hedgerows, riverbanks, marshes, and old fields.

Migration between these ranges can include a nonstop crossing of the Gulf of Mexico and Caribbean, up to about 900 miles, between Panama or Mexico and the eastern United States, part of a round trip that can total roughly 1,600 km.

Monthly presence records peak sharply in May, with secondary highs from June through August, consistent with the height of the breeding season in eastern North America; numbers drop off through fall and winter as birds move toward Central America and Mexico. These figures reflect observation counts rather than true population size or complete range.

Ruby-throated hummingbirds are solitary and diurnal, coming together only briefly to mate. Males establish and defend territories, first warning intruding males with a repeated, rising-volume note and, if that fails, chasing and jabbing with the bill or striking with the feet.

On cold nights, they conserve energy by entering hypothermic torpor, cooling their body and slowing bodily functions much like a brief hibernation.

Before migrating, birds can double their body mass in fat, then burn through that entire reserve during a nonstop, roughly 20-hour crossing of the Gulf of Mexico when no food or water is available; the return north is timed to coincide with the flowering of food plants on the breeding grounds.

Their flight is powered by one of the highest metabolic rates in the animal kingdom: a resting heart rate up to 1,260 beats per minute, around 250 breaths per minute, and oxygen consumption roughly ten times higher per gram of muscle than an elite human athlete during flight. Flight muscles make up 25 to 30 percent of body weight, and a wing that rotates nearly 180 degrees at the shoulder lets the bird hover, fly backward, and beat its wings up to 80 times per second.

Vocal communication is limited mostly to rapid, squeaky chips or chirps used as threats, such as when a male warns another male that has entered his territory before resorting to a physical chase.

Visual signals matter too: males flash their red gorget and perform a shuttle display, flying in rapid side-to-side arcs, or a dive display, looping high above a female while producing a rapid tik-tik-tik wing sound; a fainter whining sound can also come from the outer tail feathers as he flies over her and spreads his tail.

Ruby-throated hummingbirds see into the blue-violet and near-ultraviolet range, roughly 370 to 570 nm, likely helping them locate and judge flowers, and they may also use scent to detect food sources.

Floral nectar is the ruby-throated hummingbird's main fuel, and it favors red, tubular flowers such as red buckeye, cardinal flower, trumpet creeper, coral honeysuckle, red morning-glory, columbine, and fire-pink. It hovers above a bloom and uses its long, slender bill to draw out the nectar.

Some of these plants appear adapted specifically for the bird: trumpet creeper, a woodland vine, seems shaped to be pollinated by ruby-throated hummingbirds as they feed, making the bird an important pollinator wherever it forages.

Nectar alone cannot meet its needs, so the bird also eats small insects and other arthropods, including mosquitoes, gnats, fruit flies, small bees, and spiders, which supply protein it cannot get from sugar water alone. When nectar becomes scarce, it turns to tree sap instead.

Given its tiny size and relentless metabolism, a ruby-throated hummingbird consumes roughly twice its body weight in food every day.

Breeding runs from March to July, peaking around mid-May, and the mating system is polygynous with no lasting pair bond: males and females part immediately after copulation, and the female alone raises the young.

Males arrive on the breeding grounds first and stake out a territory, then court entering females with a dive display, rising 2.45 to 3.1 m above and swinging 1.5 to 1.8 m to each side of her, followed by rapid horizontal arcs less than half a meter in front of her if she perches. A receptive female responds with a call and a solicitous posture, tail cocked and wings drooped.

The female alone selects the site, usually on a small, downward-sloping limb 3.1 to 12.2 m up in a deciduous tree such as oak, hornbeam, birch, poplar, or hackberry, and builds a nest of bud scales bound with spider silk, lined with plant down and animal hair, and camouflaged outside with lichen. She lays 1 to 3 eggs, usually two, each about 12.9 by 8.5 mm, and incubates them for 10 to 14 days.

Chicks hatch altricial and are fed by regurgitation one to three times an hour; they fledge at 18 to 22 days old and become independent 4 to 7 days later, around 22 to 25 days of age. Females can raise up to three broods a year, and birds can breed for the first time at one year old.

An estimated 34 to 36 million ruby-throated hummingbirds occupied the eastern North American breeding range as of 2021, making it the most numerous hummingbird species on the continent. Numbers grew substantially from 1970 through the early 2000s but then fell by 17 percent by the 2021 census.

Ecologically, the species acts mainly as a pollinator, visiting a wide range of native and cultivated flowering plants; trumpet creeper appears specifically adapted to pollination by this bird. Where its range overlaps with other hummingbird species, it typically competes for food and tends to be subordinate to them.

The IUCN Red List classifies the ruby-throated hummingbird as Least Concern, reflecting its large numbers and wide breeding range across eastern North America.

During the nineteenth century, the species was hunted for its brilliant plumage as a collector's prize, but this pressure never pushed the population toward threatened status.

Today it is protected under the Migratory Bird Treaty between the United States and Canada and listed under CITES Appendix II. Despite this protection and decades of population growth, the 2021 census recorded a 17 percent decline from the previous count, even as the species remains far more numerous than most other North American hummingbirds, several of which are declining significantly.

The ruby-throated hummingbird carries significance in Native American mythology, reflecting a long-standing cultural presence across the communities of eastern North America, though the specific stories involved are not detailed in the available material.

Beyond folklore, the bird has practical value to people: it pollinates both wild and cultivated plants, a service that benefits crops as well as native ecosystems.

1. During courtship dives, a male's wings can beat up to 200 times per second, more than double the roughly 90 beats per second used in normal flight.
2. A resting bird's heart can beat up to 1,260 times per minute, and it breathes about 250 times per minute even without exertion.
3. Flight muscles make up 25 to 30 percent of its body weight, giving it the strength to hover, fly backward, and rotate its wings almost 180 degrees at the shoulder.
4. Nests are so well camouflaged with lichen that old ones may be reused, and simply repaired, for several breeding seasons in a row.
5. During fall migration along the Gulf Coast, older birds fare better than first-year migrants, carrying higher body weights and larger fuel reserves for the crossing.