I can’t recall when I saw my first hummingbird, but I clearly remember my son’s first sighting. He was 6, on the porch swing of his great-grandmother’s lakeside cottage in the Adirondacks. “Wow,” he said. “That’s an awfully big fly.” The iridescent little buzzer was hovering above us for quick nips of sugar water from a hummingbird feeder suspended from the porch rafters. After reading “The Glitter in the Green,” Jon Dunn’s fantastically informative book about hummingbirds, I now know with certainty that it was a Ruby-throated Hummingbird. Why? Because that is the only species of Trochilidae that breeds in the northeastern United States. Mr. Dunn, a natural-history writer and photographer, lives in Scotland’s Shetland Islands, which are devoid of hummingbirds, since they are found exclusively in the Americas. He became fascinated with the cabinet of hummingbirds he saw as a boy in London’s Museum of Natural History; unlike the blue tits and goldfinches he knew from his home in England’s Somerset countryside, these tiny, jewel-like birds looked as if they were “dipped in rainbows.” In his pursuit of what he calls “the glitter in the green,” Mr. Dunn cooked up a plan to see as many of the more than 300 species of hummingbirds as he could—particularly rare or threatened varieties which turn up in terrains at “the very limits of what [is] possible for [their] kind.” His quest takes him the full length of hummingbirds’ 9,000-mile range in the Americas, from a few hundred miles south of the Arctic Circle in Alaska, where he seeks the migrating Rufous Hummingbird, to a few hundred miles north of the Antarctic Circle in Tierra del Fuego, in search of the Green-backed Firecrown. Along the way, Mr. Dunn spots dozens and dozens of spectacular varieties, whose descriptive names often reference gemstones, flowers and classical myths. In Costa Rica alone, his many finds include Crowned Woodnymphs, Blue-throated Goldentails, Band-tailed Barbthroats, Canivet’s Emeralds, Lesser Violetears, Magenta-throated Woodstars and Black-crested Coquettes. (Many are pictured in this book, but you can see more in the documentary narrated by David Attenborough, “Jewelled Messengers,” which includes an extraordinary mating dance by a male Wire-crested Thorntail, set to a pulsing tango.) Unlike many birdwatchers, Mr. Dunn is neither an obsessive listmaker nor a competitive birder. What drives him is not numbers but a desire to see specific species—and to catch them on camera. When he does, his excitement is contagious. After finally spotting a Marvelous Spatuletail in Peru, he compares his elation—“a joy so pure and unadulterated it caught me by surprise”—to what he felt at the start of a childhood holiday at his grandmother’s farmhouse in Cornwall. A Marvelous Spatuletail hummingbird. Photo: Jon Dunn “The Glitter in the Green” braids the cultural history and daunting needs and feats of these wondrous birds with vivid accounts of the author’s sometimes hazardous, far-flung mountain, forest and island expeditions (threatened by bears in Alaska and political unrest in Bolivia, among other perils). Exceedingly well-researched and packed with fascinating lore, it should appeal to avid birders and general readers alike. Two quibbles: More informative captions on the photographs would have been welcome, including where each shot was taken. A more troubling omission is the lack of source citations for the plethora of information gathered in this volume. Like the wild English orchids Mr. Dunn tracked for his previous book, “Orchid Summer” (2018), hummingbirds have evoked fanatical passion for centuries—in part due to their diminutive size and incredible speed, but especially for their spectacular, iridescent plumage. Fortunately, Mr. Dunn’s prose has the necessary sparkle to do his subject justice. He compares the feathers of a Coppery-headed Emerald spotted in Costa Rica to “the patina developing on a Henry Moore bronze,” and describes the slender streamer tails of Brilliant Long-tailed Sylphs in Ecuador “searing through the gloom like the taillights of speeding cars in manga cartoons.” In the Beagle Channel’s lead-gray waters, Southern Giant Petrels patrol, “as ugly as xenophobia.” His descriptions of landscapes, whether thriving or blighted, are equally striking. The white screen of smoke from Alaska’s Swan Lake wildfires is likened to “viewing the world through an apocalyptic cataract.” Mr. Dunn doesn’t overwhelm us with facts—there is little here about hummingbirds’ evolution or gestation—but those he includes go down as easily as sugar water. The only birds that can fly forward, backward and sideways (and hover!), hummingbirds are propelled by wings that beat between 50 and 200 times per second, a blur to the human eye. In flight, their hearts clock 1,200 beats per minute (versus an average 80 heartbeats per minute for humans). To fuel their hyped-up, warm-blooded metabolisms, hummingbirds require about 4,000 calories per hour—including protein from insects snatched midair, but mostly plant nectar, which they extract from blossoms with thin bills and long, forked tongues that, when retracted, coil inside their heads, around their skulls and eyes. Humans would need to consume more than 150,000 calories per day if our energy requirements were similar. That’s a lot of trail mix. Black Jacobin Florisuga fusca Photo: Jon Dunn Although their collective noun is a bouquet of hummingbirds, Mr. Dunn says it’s a misnomer for these “infamously pugnacious,” territorial scrappers whose average lifespan is compressed into just three or four “frenetic years.” The Black Jacobins he spots in Brazil, for example, with their high-pitched calls and “Victorian mourning garb,” live “a soap opera existence packed with vociferous fights amongst themselves” and a nearly “pathological” intolerance of other hummingbirds. Mr. Dunn is as dogged at tracking hummingbirds in literature and art as he is at finding them in nature. His many cultural references include Frida Kahlo’s “Self Portrait With Thorn Necklace and Hummingbird,” Ernest Hemingway’s hummingbird haven in his Finca Vigía garden in Cuba and Pablo Neruda’s “Ode to the Hummingbird.” There’s an amusing story about Ian Fleming, an avid birdwatcher, and the American ornithologist James Bond. Also fascinating is the history of Robinson Crusoe Island, off the coast of Chile, where Mr. Dunn hoped to see a rare Juan Fernández Firecrown. We learn the sorry saga of a mutinous Scottish sailor stranded there in 1704 who became the inspiration for Daniel Defoe’s novel—which gave the island its modern name. Unfortunately, hummingbirds’ beauty has long threatened their well-being. Their gorgeous plumage fed the demand for Christian-themed feather mosaics in 16th-century Spain. In 19th-century England, avid collectors filled cabinets of curiosities with thousands of dead hummingbirds. The fashion industry—“murderous millinery” in particular—was especially devastating to their numbers. During his travels, the author was horrified to see husks of hummingbirds strung up “like strings of chillies” and sold as love charms in Mexican markets. Mr. Dunn worries about the future of these birds for whom “the clock of extinction is ticking loudly,” threatened by loss of habitat, climate change and man-introduced predators like cats. “I had a fear that hummingbirds might prove to be the most colourful canary in the coalmine, prophets of change that did not bode well for them or us alike,” he writes. Given their plummeting numbers, he confesses that a sense of urgency drove him to see endangered species before they disappear entirely. “The Glitter in the Green” is a lustrous record of what would be lost. —Ms. McAlpin reviews books regularly for the Journal, and the Christian Science Monitor. Copyright ©2020 Dow Jones & Company, Inc. 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