Ruby-throated Hummingbird

Identification

The adult male carries a gorget of iridescent scarlet that can read as a black hole in the throat when the light is wrong — angle is everything with this bird. Above, the back and crown are metallic grass-green; below, the belly and flanks are greyish white; the tail is dark and forked with small white tips on the outer feathers. Females and immatures show no red at all: the throat is clean white, sometimes with faint dark speckling down the centre, the back is the same green, and the tail is broader with larger white corners. Across most of its range it is the only hummingbird present, so the real identification work is ruling out western vagrants — check the throat first, then the tail pattern.

In hovering flight the wings beat better than 50 times a second. The bird can fly forward, backward and briefly upside down, but it cannot walk; the legs are for perching and scratching only. It feeds every ten or fifteen minutes through the day, taking nectar from tubular flowers and hunting small flies, gnats and spiders for protein, which matters most while chicks are growing. Southbound birds fatten until they weigh nearly twice their lean mass, then many cross the Gulf of Mexico in a single nonstop flight of 800 km or more. Males arrive on the breeding grounds ahead of the females and immediately claim a patch of flowers, driving off bees, butterflies and other hummingbirds along a chase route that stays much the same day after day.

In the east, the first males reach the Gulf coast in March and follow the flowering north through spring. A patch of red or orange tubular flowers — salvia, coral honeysuckle, trumpet vine — is more dependable than any feeder; if you do hang one, mix one part plain white sugar to four parts water, skip the red dye, and change it every two days in hot weather. The southbound movement in September is fast and concentrated, and a single garden can host a different bird every day for a week.

The cost of being a hummingbird

Hovering is expensive. The wings beat faster than most eyes can follow, and the bird must feed every ten or fifteen minutes through the day to keep up. Nectar supplies the energy, but it is not a complete diet: small flies, gnats, aphids and spiders supply the protein, and these matter most while chicks are growing and before migration.

At night, and in cold or wet weather when food cannot be found, a hummingbird can drop into torpor - a controlled reduction in body temperature and metabolism that is close to hibernation for a few hours. This is how a bird that weighs about as much as a penny survives a frosty night. In the morning it needs a period of shivering and feeding before it can fly properly again.

Iridescence and display

The red gorget of the male is not pigment but structure. Microscopic layers in the feather reflect light at particular angles, so the throat blazes scarlet when the bird faces the sun and turns dull black when it does not. Angle is everything, and a bird seen in the wrong light can look like a different species.

Males arrive on the breeding grounds ahead of the females and claim a patch of flowers, driving off bees, butterflies and other hummingbirds along a route that stays much the same day after day. The display flight is a series of wide, sweeping arcs, and the wings produce a metallic buzz or trill at the bottom of each pass rather than a song.

Confusion risks

Across the east there is little else to confuse it with, so the real work is ruling out western vagrants. Start with the throat, then look at the tail. A male with a full red gorget and a dark, deeply forked tail with small white tips is a Ruby-throated; a broad, rounded tail with large white corners belongs to a female or immature bird.

Any hummingbird in the east that shows rufous on the flanks, back or tail base should be examined closely, since Rufous and other western species do turn up in autumn. Note the tail pattern, the face pattern and the exact shade of the underparts before deciding.

Flowers, feeders and the season

In the east the first males reach the Gulf coast in March, and the wave follows the flowering north through spring. A patch of red or orange tubular flowers - salvia, coral honeysuckle, trumpet vine, bee balm - is more dependable than any feeder, because it also attracts the small insects the birds need.

If you hang a feeder, mix one part plain white sugar to four parts water, skip the red dye, and change the sugar water every two days in hot weather and more often if it looks cloudy. Clean the feeder thoroughly each time, since mould and fermented syrup are a genuine hazard. The southbound movement in September is fast and concentrated, and a single garden can host a different bird every day for a week.

Fieldcraft and conservation notes

Sit still and let the birds come to you. Hummingbirds are aggressive towards each other but curious about people, and a motionless observer beside a flower bed will often be inspected at close range. Photograph them without flash at close range and without disturbing a nest; a nest is a tiny cup of plant down and lichen on a horizontal branch, and it is easy to destroy by accident.

The species is widespread, but the same features that make it easy to observe also make it vulnerable: it depends on flowers and insects along a migration route that crosses the Gulf of Mexico in a single nonstop flight, so habitat loss on either side of the crossing affects the whole population. Pesticide use in gardens removes the insects that supply protein.