Courtesy photo/Charles Lorenz
By M. KATHY RAINES
Waves and waves of slender, glittery ruby-throated hummingbirds have ushered in fall migration, now in full swing, as they guzzle nectar from blooms and feeders to fortify themselves for journeys to wintering grounds in Mexico and Central America. Local birders have been scrambling to put up enough feeders for these hungry, territorial customers.
As early as August, males arrive, their necks a parfait of iridescent colors—ruby red, green and white—the shimmer created by light waves interacting with the feathers’ complex structures. The male’s red throat patch, or gorget, looks different at varied angles—sometimes appearing to be black—a perception he apparently controls. To show off his good health, the male tilts his feathers to best exhibit this scarlet jewel to both rivals and would-be mates.
Juveniles follow—with some autumnal males already sporting a few red feathers—alongside the more subtly tinted females; for camouflage, they, as sole nesters, require more muted colors—green above, whitish below. Though they never walk, ruby-throats have tiny, lightweight feet which they employ for perching, grooming and, for females, nest-building.
Though the ruby-throated hummingbirds (Archilochus colubris) who refuel in the Valley likely migrate alongside the Gulf, some hummers travel across it. Prior to migration, the tiny birds bulk up, sometimes nearly doubling their weight a week or two before departure. Ruby-throats, the only hummingbirds to breed in the Eastern U.S., also inhabit Texas woods, orchards and yards east of the Edwards Plateau. Only rarely does a ruby-throat overwinter in the Valley.
Ruby-throated hummingbirds, as we see from recovered banded birds, exhibit site fidelity, revisiting locales where they’ve felt safe and enjoyed plentiful food. Hummingbird banding is on the upswing, though recovery of banded birds is rare. Texas Master Naturalist Marilyn Lorenz has enjoyed banding hummingbirds, saying she loves “the tiny little, jewel-like bands” placed on them. The birds, who “really don’t like being banded,” she says, “hum like tiny little angry buzz saws, and we can’t help laughing because they are so small and so angry, and, of course, we are not going to hurt them, just add a little jewelry.”
Helicoptering up, down, forwards, backwards, at a slant, and occasionally upside down, this feisty creature provides amusement to many. Harlingen resident Sandra Mink, sitting in her backyard in late September, said she “was threatened by two tiny ruby-throats who hovered for an instant, flashing their brilliant red gorgets”, then “were off like a shot to parts unknown.” Ruby-throats make chipping calls and hum with their wings.
A ruby-throat may flap its wings 53 times per second and fly 30 mph going forward and up to 60 mph when diving. Its large heart, 2.5% of its body weight, beats from 500 to 1,200 beats per minute. With this stunning metabolism, it must eat constantly. Besides nectar, this hummer consumes insects, which it catches in mid-air or gleans from trees, and snatches spiders from webs. It also drinks tree sap—some drilled out by sapsuckers— a convenience when the hummingbird reaches breeding grounds before plants have blossomed and insects hatched.
A hummingbird requires sucrose, which it obtains from flowers of many varieties, but especially red, tubular ones—like those of our native Turk’s cap—which may have evolved alongside of it. Poking its long bill into a blossom, its tongue—forked and fringed at the tip—wraps around drops of nectar which it yanks back into its bill and swallows. The hummer dips back into the flower, repeating this process perhaps twenty times a second.
To conserve energy at night, the hummingbird slows its processes, becoming torpid. Its body temperature may drop below 60 degrees Fahrenheit with its heartbeat slowing to less than 50 beats per minute.
Recovering from torpor, the bird vibrates its wings, creating heat, which warms its blood supply, bringing its temperature up to 100 or so degrees.
After the male defends about ¼ acre of territory and makes elaborate, often U-shaped courtship dives, he mates with a female. Then she is on her own. She makes a nest of fibrous plants glued with spider’s silk, usually on a sideways sloping limb. People have found hummingbird nests on wires, chains or extension cords, however. Only she nurtures the chicks.
To help nourish migrating hummers, as well as our resident buff-bellied hummingbirds, we can plant blossoming shrubs, especially native, insect-attracting ones like Turk’s cap and Esperanza, and put up feeders that are relatively inaccessible to predators. Hummingbirds should be fed one part white sugar—other types aren’t healthy—to four parts water. Every few days—oftener in summer—feeders must be scrubbed to rid them of harmful mold or pathogens. Techniques vary. Most recommend mixing warm water with vinegar or small amounts of hydrogen peroxide or bleach.