The Hummingbird Handbook

One:
Hummingbird Trivia: Facts, Fictions & Folklore

Hummingbirds have fascinated humans for millennia. Long before European explorers set foot in the New World—the only place on Earth where hummingbirds live—native peoples throughout the Americas were enraptured by hummingbirds; some cultures revered them and even used hummingbird feathers and skins in their clothing. When Europeans reached the Americas on the eve of the Age of Reason, they too were smitten by hummingbirds, and so across world cultures, myths, legends, and fanciful fictions surrounded these tiny birds.

Most early explorations of the New World included naturalists either by definition or by hobby. They encountered a natural and cultural world completely foreign to them, and lands populated by creatures never seen outside of the Americas. As specimens poured into Europe, the scientists of the day began to unravel some of the mysteries surrounding hummingbirds, but even to modern science, hummers remain enigmatic in many ways, and ongoing research continues to fill holes in our understanding of these amazing little birds.

With hummingbirds, the facts often prove more fascinating than the fictions, and as researchers unlock the secrets about the ecology and biology of these birds in all their diversity, more questions arise. That of course, is the nature and beauty of science: questions beget answers through application of scientific method, and answers in turn almost always beget further questions. This chapter delves into those questions and answers and more questions about these inscrutable birds.

All That Glitters

With just a turn of the head, a hummingbird explodes in iridescent radiance, its gorget—the patch of colorful feathers covering its throat—instantly conflagrant in shades that cover the color spectrum, depending on the species. These dazzling colors derive from the feather structure rather than from pigmentation. Each tiny iridescent feather has barbules that are densely packed with layers of microscopic platelets filled with air bubbles. These platelets reflect and refract light waves, explains Bob Sundstrom of BirdNote, “creating color in the manner of sun glinting off oily film on water.”

The color you see in a hummingbird’s gorget depends on the angle and quality of the light being reflected and refracted by the specialized throat feathers (aka spangles). In one moment the gorget (and in some species, the crown as well) appears black, deep gray, dark bronze, or deep purple, and then the bird turns its head and the throat bursts into magnificent colors like a neon flashbulb. Iridescent gorgets and crowns are most prevalent in males, with perhaps 70 percent of species being sexually dimorphic (that is, males and females look different). In some dimorphic species, even the females have at least a partial gorget of iridescent feathers.

Hummers vary tremendously in the color and arrangement of their iridescent parts. Even among the handful of hummingbird species that are widespread in the United States, the variety in colors is impressive, from the blazing orange gorgets of male Allen’s and Rufous Hummers, to the incredible iridescent magenta throat, face, and crown of the beautiful male Anna’s Hummer, to the closely related Costa’s Hummingbird, whose head is enwrapped in royal purple, with a gorget that tapers into long mustachelike points on each side of his head.

The term “gorget,” incidentally, derives from the shaped metal sheet worn as part of body armor beginning in the Middle Ages. By the 1500s, the plate-metal gorget had reached its zenith in both design and function, and soon became ornamental as well, signifying status and rank, a tradition that continues today in some militaries. It seems an apt moniker for the vibrant adornment of hummingbirds—and yes, the word “gorgeous” is etymologically related!

The vast majority of hummingbird species live in Mexico, the Caribbean, Central America, and South America, and in these more southerly latitudes, hummers reach the pinnacle of their mind-boggling diversity. Some species sport iridescent feathers over nearly their entire bodies; others combine incredible iridescence with opulent adornments, such as streaming bannerlike tails and flamboyant crests.

The amazing hummingbirds, however, have not cornered the market on iridescent feathers. Many other birds share this trait, including grackles and blackbirds, swallows, various ducks, and peacocks. But few would argue that hummingbirds take iridescence to magnificent extremes.

Extremes Among the Extreme

All hummingbirds range from small to tiny—almost.

The largest of the 340-odd species is—you guessed it—the Giant Hummingbird (Patagona gigas). Imagine a hummingbird 9 inches long with a wingspan of more than 8 inches. This enigmatic denizen of the Andes is bigger than a Barn Swallow and as long as a Robin, though much slenderer. And like all hummers, even this behemoth is extremely light in weight, at about 0.85 ounces, and capable of amazingly acrobatic flight; but compared to much smaller hummers it appears somewhat cumbersome and hovers at a rate of only about 15 wingbeats per second—on the slow side for a hummingbird.

At the other end of the hummingbird size spectrum, myriad species weigh in at a mere fraction of the bulk of the Giant Hummer. But even among the Lilliputians, there is a standard bearer: the tiny Bee Hummingbird (Mellisuga helenae), endemic to the Cuban archipelago. The world’s smallest bird of all, the Bee Hummingbird weighs less than a tenth of an ounce—less than a U.S. penny—and is just barely over 2 inches long.

Fit the Bill

A casual observation might suggest that hummingbirds use their long, thin, dainty beaks like straws; however, beginning early in the 19th century, scientists realized that the tip of a hummingbird’s tongue forks into two tiny tubes, and so they postulated that the birds must drink nectar through capillary action, the same mechanism that allows a towel to draw in water. Turns out, the scientists were wrong—for well more than a century.

Inquisitive scientists and high-speed motion photography finally cracked the code in 2011, when researchers Margaret Rubega and Alejandro Rico-Guevara discovered that hummingbirds feed via a pistonlike method. They lap up nectar with their tongues, the tiny forks at the tip springing open to gather fluid; then the tongue retracts as the bill squeezes shut, compressing the tongue and allowing the bird to lap up the nectar. They repeat this high-speed lapping 15 to 20 times per second.

Another enduring mystery—among the many with these enigmatic birds—is how they catch insects, which make up a significant and important part of their diets. Again, relying on high-speed frame-by-frame photography, researchers learned that hummers can flex their lower bill downward to get it out of the way and widen the base, and then snap the bill closed at blinding speed. Combined with their aerial agility, this adaptation for catching insects on the wing allows hummingbirds to obtain life-sustaining protein, fat, amino acids, and other important nutrients.

Bill lengths and shapes vary dramatically throughout the hummingbird world, and some species coevolved with specific flowers that provide their primary nectar sources. Many hummingbirds have bills specifically adapted to fit certain flower species, and both the shape and length of the bill, and the shape and structure of the flower tube can coevolve regionally and temporally between two species. Studies in the evolutionary relationship between pollinators, such as hummingbirds and bees, and flowers that need to be pollinated, continue to provide amazing insights. One such research project, headed by Lena Hileman at the University of Kansas, revealed that the flowers of various Penstemon species show either bee or hummingbird adaptation: species that are adapted to bee pollination are generally bluish or purplish, with a flower tube of sufficient diameter to allow bees to enter and a stamen positioned to deposit pollen on the backs of bees. Conversely, species adapted for pollination by hummingbirds are red or orange-red with narrow openings to allow only the bill and/or tongue of a hummingbird to enter; they don’t need to offer a landing pad.

All this coevolution has led to some truly bizarre flowers but also to some hummingbirds with extraordinary bills. Among the most idiosyncratic is the Sword-billed Hummingbird, native to Andean South America. This bird’s daggerlike bill is nearly as long as its entire body, stretching to almost 4 inches. This long bill allows the Sword-billed Hummer to feed on long-tubed flowers whose nectar is inaccessible to other species, especially and most notably the beautiful pink blooms of northern banana passionflower (Passiflora mixta). The dramatic coevolution of these two species, which occupy the same range in the Andes, is an example of a mutualistic relationship: the flower is pollinated by the hummingbird, and the bird is rewarded with a rich source of nectar.

American Idols

Hummingbirds are as American as apple pie; or more accurately, as American as pastel de manzana and torta de maçã (Spanish and Portuguese, respectively, for “apple pie”). After all, hummingbirds are native only to the Americas, mostly Central and South America. In Brazil, a Portuguese-speaking nation, the elegant word for hummingbird is beija flor (from beijar, “to kiss,” and flor, “flower”)—hence we arrive at “flower kisser,” more or less—certainly a visually descriptive moniker. In Spanish, the predominant language of Central and South America, the word for hummingbird is colibrí, which is thought to derive from the French Caribbean.

In Latin America, colloquial names for hummingbird are often more colorful. Mexican synonyms include chuparosa (“rose sipper”), florimulgo (“flower milker”), pájaro mosca (“fly bird”), chupamiel (“honey sipper”), joyas voladoras (“flying jewels”), and others. Indigenous peoples of the Americas had their own names for these tiny birds; to the Mayans, they were x-ts’unu’um.

Hummingbirds are key players in Native American mythology, and perhaps nowhere is this more evident than in the massive hummingbird mosaic in the Nazca Lines in the Nazca Desert of southern Peru. This geoglyph, 320 feet long and 216 feet wide, was created around 2,000 years ago by the indigenous Nazca people by digging through the topsoil layer of dark pebbles to reveal a lighter substrate. Farther north, in what is now Central America and Mexico, hummingbirds played a significant role in Mayan and Aztec culture. The Aztec hummingbird deity, Huitzilopochtli, is a god of war to whom they made human sacrifices; other Native American cultures attributed special significance to hummingbirds, which are central characters in many indigenous legends.

Nearly as soon as they set anchor in American waters, European explorers became enamored of hummingbirds. As was the customary scientific process, naturalists of the era collected as many specimens as they could, and voluminous collections accrued in the hands of European naturalists, artists, museums, universities, and, notably, private individuals of considerable means. In some cases, these preserved hummingbirds served as models for beautiful artistic renditions, often included in books about New World birds.

But the European discovery of America’s hummingbirds also coincided with the Continent’s craze for feather-adorned fashions, and that calamitous convergence proved disastrous for countless avian species.

Trouble in Paradise

Unfortunately for the hummingbirds, Europeans soon began desiring them to make expensive clothing, jewelry, flowerlike arrangements, and other art pieces. Not long ago, a British auction house offered for sale—for about $50,000—an elaborate Victorian-era fireplace with a diorama of more than 100 stuffed hummingbirds arranged on branches mounted between two large panes of glass and framed in gilded, delicately carved metal. The 19th-century world of high fashion fostered a fascination with colorful and exotic creatures from the New World, Asia, and beyond; and the demand for fancy-feathered women’s hats drove a British, Continental, and even American craze for brilliant plumes, feathers, and even entire stuffed birds, an infatuation that decimated countless bird populations throughout the world.

Luckily, however, by the early 20th century, outcry led to reform, first in the United States, later in England. Though George Bird Grinnell, the influential editor of Forest and Stream, was perhaps the first to publicly rail against the absurd excesses of the feather trade in the 1880s, among the most vocal and insightful of the change-minded crusaders aiming to eliminate the merciless destruction of bird populations was William Temple Hornaday, whose book Our Vanishing Wildlife (1913) brought needed public and political attention to the plumage trade that was rapidly destroying whole bird populations. James Buckland, the tireless champion of the English plumage bill that would eventually curtail that country’s participation in the decimation of the world’s birds, ran the shocking numbers in December 1913: “Here are the totals of just a few species whose plumage has been sold during the past twelve months at the London feather sales: 216,603 Kingfishers; 21,318 Crowned Pigeons, 20,715 quills of the White Crane; 17,711 Birds-of-Paradise; 5,794 pairs of Macaw wings; 4,112 Hummingbirds; and so on, through the whole list of brilliantly plumaged birds.”

Hummingbirds in Central and South America were ruthlessly hunted to sate the demands of high fashion—in one weeklong London auction, a staggering 12,000 hummingbirds were among an unfathomable 350,000 bird skins sold. Hummingbirds were prized for their magnificent iridescence, and in 1914, American journalist Rene Bache wrote a scathing indictment, carrying the sardonic headline, “By All Means Buy A Humming Bird Coat, They are the latest thing and the cost is only a trifling $25,000.” That’s about $650,000 today. Bache decried that the knee-length coat required thousands of hummingbird skins, but the insatiable demand in Europe to create ever-more elaborate fashions meant entire species were pushed to the brink of extinction.

Thankfully public outrage was growing sufficiently that new and revolutionary wildlife-protection laws were being debated and enacted. In 1914, Bird Lore, the bimonthly magazine published by the fledgling Audubon Society, reported thus:

In Paris, France, on March 9, 1914, the woman’s paper, La Vie Feminine, gave its inauguration reception at the Galerie d’ Excelsior, 88 Champs Elysees. The lecturer was the novelist Pierre Loti (Lieut. L. M. J. Viaud), who was asked to speak about women in Turkey. His opening remarks may be of interest to the Audubon Society: “Looking at you from this platform, I see a surging mass of feathers, which your hat-makers insist upon placing—some straight in front, others over one ear, then again a plume trails over the back of the head, in a weeping-willow style, giving the impression of unrest. I will end my digression by telling you something profoundly sad. Among the plumes on your hats I distinguish innumerable [egrets], quantities of Birds-of-Paradise, and, as I turn my eyes away, I think of the ruthless massacres which bird-hunters are carrying on for your pleasure and vanity. Poor little winged world, inoffensive and charming, which in half a century, thanks to you, will be found nowhere! I recall some specimens, the most wonderful, which have already disappeared, with no possible return. What a sacrilege! What a crime! To have sent into oblivion a species of bird-life which no mortal can re-create in this world! Ladies, I ask mercy for the birds of fair plumage. Believe me, all of you will be just as lovely, and appear less cruel, when you have discarded the covering of these little bodies, which you now wear on your hats.”

Hummingbirds and many other members of the avian world were spared, as strict laws were enacted to protect them, and hummingbirds are now celebrated throughout the Americas. These feathered gems even support a robust subculture in ecotourism. Hummingbird fans flock to locations known to support diverse and intriguing species. Throughout the Americas, tour guides, lodges, parks, sanctuaries, festivals, and even entire communities cater to and are supported by itinerant enthusiasts who love these little American icons.

We’re on the Money!

And on the stamps, and even on the coins. Hummingbirds are so universally beloved that they have appeared on currency, coins, and postage stamps throughout the Americas, from Brazil to Canada. In many instances, currency and stamps depicting hummingbirds present beautifully rendered artwork, and collectors could easily specialize in collecting postage stamps or currency adorned with these mesmerizing birds. Several times, the United States Postal Service (USPS) has issued hummingbird stamps. In 1992, for example, the USPS issued a set of five stamps depicting five different North American species: the Ruby-throated, Broad-billed, Costa’s, Calliope, and Rufous Hummingbirds. Most Central and South American nations, including Caribbean nations, have issued hummingbird postage stamps as well, but they alone—rather than the United States or Canada—have also, in many cases, given hummingbirds a prominent place on currency.

Spread the Wealth

Hummingbirds and the flowers they feed from help one another, a textbook example of a symbiotic relationship. The birds seek sugary nectar from within the blooms, and in so doing, inadvertently gather pollen, which sticks to their bills and forehead. When the birds feed at other flowers of the same species, the pollen is transferred from plant to plant. Bees and butterflies also cross-pollinate flowers, but through evolutionary processes, countless flowering plants have developed characteristics that favor pollination by one type of animal or another. Flowers evolved for hummingbird pollination tend toward bright shades, lack strong scent (insects use scent to find flowers; birds use vision), and are structured in ways that allow hummingbird bills and tongues to reach the nectar while excluding bees and butterflies from doing so. Throughout the Americas, in fact, many species of flowers rely exclusively on hummingbirds for pollination. For example, in eastern North America, fire pink (Silene virginica), a bright red wildflower, is primarily pollinated by the familiar Ruby-throated Hummingbird—just one of countless examples of a species dependent on hummingbirds.

Aerial Acrobats Beyond Compare

The bird world is full of amazing flyers: falcons diving at death-defying speeds, swifts and swallows maneuvering in hot pursuit of bugs, accipiters dodging through dense forest at perilous velocity. But no bird can match the hummingbird for agility on the wing. Hummingbirds are experts at hovering, the strategy employed by most species for feeding on the nectar of flowers. They can also fly backward and even, for brief moments, upside down. Some species perform amazing courtship flights, diving from aloft at bedazzling speeds only to check their plunge suddenly, tracing an arc too fast for the human eye to track.

Hummingbirds have evolved an insectlike flight adaptation: other birds create the lift needed for flight with each downstroke of the wing, but on the upstroke, the outer wing folds inward toward the body in preparation for the next downstroke. In other words, typical bird flight is achieved by flapping the wings up and down. Hummingbirds, however, rotate, or twist, their upper arm bones (humeri) to invert the wing and gain lift from the upstroke as well as the downstroke. The result? The most agile birds on the planet.

Now That’s a Blur!

The advent of high-speed motion photography has allowed scientists to accurately measure and study wing movements that are way too fast for the human eye to see. We now know that, depending on the species, hummingbirds flap their wings from about 10 to more than 80 times per second while hovering, and even faster during the courtship display dives of some species.

Moreover, hummingbirds can fly very fast, routinely attaining speeds of 20 to 30 miles per hour and triple that during the amazing courtship display dives used by males of some species. The swiftest hummingbirds are extremely fast: Christopher James Clark, who has done extensive hummingbird research at the UC Berkeley, discovered that during its courtship dive, the male Anna’s Hummer folds its wings in to its sides, achieving an average maximum velocity of approximately 90 feet per second, the highest speed every recorded for a vertebrate, relative to size. Even more incredibly, as it pulls up, with wings spread, the bird experiences centripetal accelerations nearly nine times greater than gravitational acceleration. In short, hummers are faster than a fighter jet, relative to size, and withstand g-forces that would make the average person black out.

Pint-size Pugilists

Many hummingbird species behave aggressively toward other hummers. Even females and juveniles will defend their favorite feeding locations, but such assertiveness is especially pronounced with territorial males. A dominant male will defend “his” favorite flowers or feeder ruthlessly and relentlessly, chasing away all male interlopers. He may even chase away females, though often perceived aggression toward females of his species may be related to courting behavior. Some male hummingbirds routinely harass females until the female breeds with him, at which point she typically becomes part of the territory; however, whether or not a female builds her nest within the territory of the male with whom she mated is an open question.

Male hummingbirds defending their breeding or feeding territories typically tolerate no intrusion from fellow males of their own species and will even chase away males and females of other species. The consensus is that breeding territories may cover up to about a quarter of an acre, perhaps more, especially in open country. Feeding territories seem to vary considerably in size and scope, at least based on my own observations with Anna’s, Rufous, and Black-chinned Hummingbirds. A hummingbird’s feeding territories may include not only hummingbird feeders but also particular flowers, flowers beds, gardens, water features, or entire yards. Certain species are more bellicose than others; in one instance I had a female Rufous Hummer that so truculently guarded the feeder she claimed that she gave no quarter to either sex, of any species.

Territorially aggressive behavior in hummingbirds takes several forms, and the interactions, rarely damaging to the birds, are frenetic, fast-paced, and fascinating. It may begin with excited scolding and brilliant displays of the gorget, but the classic territorial encounter is the aggressive chase in which one hummer drives the interloper away at blinding speeds, usually chattering loudly. Rarely a brief physical battle can ensue, and in those cases, hummers can injure or even kill one another with their bills. This behavior can easily be confused with breeding-season aggression in which males actively chase females, especially when both sexes are freshly arrived from their spring migration. Once things settle down a bit, courtship season begins in earnest, and that’s when the males perform their amazing, acrobatic courtship display flights aimed at duly impressing the observing female.

During the nonbreeding season, hummingbirds may be less aggressive about defending feeding territories, but they’ll still try to monopolize a hummingbird feeder. Based on my observations with Anna’s Hummingbirds, sometimes more than one male may routinely use the same feeder, even aggressively defending it, only to have another male replace him in that role at different times during the day.