Fearsome news, dear readers, from this forlorn rural outpost—my tiny cabin on the outskirts of Bastrop, Texas. It’s a sweltering October evening, the pigeon-colored sky silent as death. On my porch a desperate combat is taking place. The battlefield is a blur of ruby-throated hummingbirds bombarding and strafing each other. They should all be in Mexico by now, but warm days entice these dawdlers to lag behind. The contested prize: a hanging globe of sugar water, stained red with food coloring. The combatants make their circle, again and again, buzzing with self-righteous fury. A lone defender hovers by the feeder valiantly fighting off the onslaught, for a time holding his ground. Then, from somewhere up high, a dull female enters the fray, transforming the dispute instantly. She brandishes an intrepid attitude, bordering restrained cruelty. All the contenders scatter like buckshot to the safety of nearby treetops. The prize is hers. Valor is not a function of physical size.
No doubt this drama plays out around endless Texas hummingbird feeders. No matter who wins the spat, there’s an outsized sense of territorial jealousy that runs in the veins of all ruby-throated hummingbirds. For their diminutive stature, these tiny tyrants live life LARGE. They make, for their size, herculean migrations—many crossing the Gulf of Mexico (or circumnavigating around it) in a single flight. They entertain and delight us all with their precision acrobatics. Like little attack helicopters, they fly straight and fast but can stop instantly, hover with ease and adjust their position up, down, or backwards with exquisite control. And you won’t find more meticulous nest builders anywhere in Bird Ville. For single mothers, nature offers no equal to a female hummer for nurturing, courage, and absolute dedication. Everything about these small creatures is a lesson in living boldly.
Even though they have been around for what must be millions of years, no hummingbird fossils have been found that would give clues to their ancestry. They live exclusively in the western hemisphere and they like it nice and warm (most are found in Central and South America). The species counts more than 300 overall, with only 18 normally found in the continental U.S. In Texas 9 species are regulars (an additional 6 have made occasional appearances). The two most common species in Texas are the black-chinned hummingbird and the ruby-throated hummingbird (they are actually close relatives). If you have hummingbirds at your feeder, there’s a 99% chance it’s one of those two. Let’s meet the ruby-throated hummingbird.
Ruby-throated hummingbirds have the largest breeding range of any north American hummer. They weigh in at a whopping 2-6 grams (like a handful of paperclips?). The adult male has a throat patch of iridescent ruby red, bordered narrowly with velvety black on the upper margin and a forked black tail with a faint violet sheen. The iridescence is directional and appears dull black from many angles (the iridescence caused by reflected light). The female also has a notched tail with outer feathers banded in green, black and white, and a white throat that may be plain or lightly marked with streaks or stipples. With extremely short legs, ruby-throated hummers cannot walk or hop—the best they can manage is to “shuffle” along a perch. Plumage is molted twice a year. Males are the smaller of the two and are deadbeat fathers. Hummers are not social, other than during courtship (which only lasts a few minutes). Not known for their repertoire, vocalizations are rapid, squeaky chirps—used mostly as threats. All in all, what we see is a strikingly beautiful, amazingly agile featherweight with a pugilistic, nasty attitude.
There are many curiosities surrounding these avian entertainers, but I wonder about the incredible physiology it takes to do what they do. For starters, under normal circumstances they beat their wings about 53 times a second (80 times/second while hovering). They breathe 250 times a minute with heartrates of up to 1260 beats per minute! They’re one of the most efficient air pumps on earth. During flight, their oxygen consumption (per gram of muscle tissue) is approximately 10 times higher than that seen for elite human athletes. On cold nights, they can voluntarily enter a Zen-like, mystical state of hypothermic torpor to conserve energy. So, what kind of a body does it take to achieve these deeds?
A strong one! Muscles make up between 25-30% of the hummer’s body weight. Unlike other birds, hummingbird wings connect only at the shoulder joint, allowing them to rotate their wings almost 180 degrees. This gives precision control to hover, fly backwards and zip all over the place with blinding speed and accuracy, similar to what you might find in some insects. Because of high energy levels, hummers feed constantly. In preparation for their annual Gulf crossing, the tiny birds can double their fat mass. They like nectar from flowers and flowering trees, but also chow down on small insects and spiders, which provide protein, minerals and vitamins. They are so swift and maneuverable as to snatch bugs right out of the sky. They may even steal sugar-rich tree sap from sapsucker wells. They have a split extendable tongue designed for getting goodies from dark, deep sources and can see into the ultraviolet spectrum, which humans can’t see. They seem to prefer red, orange or pink tubular flowers and are effective pollinators.
Everything about these birds is life in exquisite miniature. Females construct a nest about the size of a peach, usually on a small downward-sloping tree limb, near the tip. These birds are accustomed to humans, so they have been known to nest on loops of chain, wire, or even extension cords. Nesting materials include bud scales, with lichen on the exterior, bound with spider silk, and lined with fibers such as plant down (either dandelion or thistle) and animal hair, softer than the inside of your arm. It looks from below like a lichen-covered knot on a branch! Repaired annually, old nests may be used for several seasons.
Courtship is a noisy clinic in dare-devil stunt flying. The male makes a rapid tik-tik, tik-tik, tik-tik sound with his wings as he puts on a shuttle display, at the end of a side-to-side hover or during dive displays. 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 moves. He may start his performance with a power dive in a U-shaped curve in front of her. Once he has her attention, he may dart at her like a bullet, brake quickly, shoot straight up for fifty feet, and then plummet back, catching himself in mid-air just beside or in front of her. Every movement reflects the dazzling colors of his flaming neck feathers, showing clearly what an unforgettable one-night-stand he would make. If she agrees, she’ll give a call of her own and assume an inviting posture with her tail feathers cocked and her wings drooped.
Male Ruby-throated hummers are of the “slam, bam, thank you ma’am” persuasion. Realizing males are nearly as useless as an ill-trained gun dog, the female alone cares for the eggs and young. She’ll lay two white eggs and produce one to two broods each summer. Males rarely live past 5 years; almost all hummingbirds of 7 years or more in age are females. The oldest known Ruby-throated female was a bit over 9 years old when she was recaptured and released during banding operations in West Virginia. Chicks are brooded until they are feathered and properly insulated (about 12-14 days). Mom stays busy feeding her chicks as much as 3 times an hour by regurgitating, usually while she continues to hover. When the chicks are 18-22 days old, they leave the nest and make their maiden flight. Then it’s time to fatten up and prepare for migration. Life moves at a frenetic pace; mom and family are severely overscheduled!
Hummingbirds represent a species unlike any other bird on earth—brilliant, tiny, precision-flying creatures that glitter like jewels in the sun! As if paranormal spirits, they arise from emptiness and vanish again into the void—singular and fleeting. Yes, like other birds they fly. . .but in so doing, choreograph the miracle of flight into an extraordinary spectacle. Elegant as algebra, to say they are not artists is to misunderstand the nature of art. Like little transformers, at will, hummers can pass into an energy-saving stupor so deep that cardiac function teases death. Verily one could say infinitesimal sips of nectar fuel the heart of a lion, which then migrates the human equivalent of twice around the world. Such feats represent castles-in-the-air for most of the sentient world, flashing the truth that, if we look closely, we can learn about nature’s divine radiance from a mere thimbleful of fearlessness.
By Larry Gfeller