Darwin proposed sexual selection as a driver of evolution in On the Origin of Species (1859) and expanded on the idea in The Descent of Man (1871). Nothing makes sense except in the light of evolution, so the paradisiacal panoply of feather coloration makes sense only if birds have color vision. So, too, with fish—they must have color vision, whether for beauty's sake alone or as an indicator of fitness, if sexual selection drives the evolution of coloration.

It's a damn shame for birds that fish have color vision—not that anyone knew that in 1842, when angler and tackle-seller William Blacker published his Art of Angling, exhorting fly-tyers to use feathers from species such as cocks-of-the-rock (Rupicola spp.), macaws, the Resplendent Quetzal (Pharomachrus mocinno), several of the blue Cotingidae, and the birds-of-paradise (Paradisaeidae). When George Mortimer Kelson published The Salmon Fly in 1895, the theory of evolution was still roiling Victorian society. Anglers were not likely to know, much less accept, the notion that fish coloration evidenced color vision in fish. Not that the invertebrate prey of salmon were so brilliantly colored as the feathers of these birds. So why the notion that brightly colored flies would make better lures? As author Kirk Wallace Johnson explains in The Feather Thief, salmon flies are not meant to resemble prey. They are meant to provoke the salmon to protect their freshly spawned eggs from potential predators. Any object on a hook might do. Victorian England happened to be flooded with enormous shipments of exotic feathers for the millinery trade, so commerce may have motivated the emergence of ornate ties garnished with vibrant, lustrous feathers. Although Kelson claimed scientific rigor, he admitted that there was no basis for recommending any particular fly and even acknowledged that “at times a salmon will take anything…even a thing it were an outrage to call a Salmon fly.” Nevertheless, he persisted in promoting his book and in exhorting the use of avian finery for salmon lures.

Johnson draws a straight line from the Victorian obsession with exotic bird feathers for salmon flies to the 2009 theft from the Tring Museum of many bird specimens collected during that era. Edwin Rist, an American in England to further his studies as a flutist, climbed a back wall of the museum, broke a window, climbed in, stuffed 299 specimens into a suitcase, returned home, removed the tags, pulled the bright feathers and discarded the rest, and then set about selling his loot on the Internet, ostensibly to raise money to buy a new flute. The theft was discovered a month later, but by then the damage was done. Of the 174 skins seized from Rist, 72 were missing tags. Other specimen thefts from museums had prompted the formation of an online community of curators to share information about the constant black-market demand for their treasures. Yet, Johnson asserts, the Tring staff had no idea that the fly-tying world was so enamored of the feathers of species now protected by law and so rare that any one skin could be worth thousands of dollars, putting their holdings at risk.

Even readers who already know about this execrable atrocity will agonize at reading that among the 299 skins taken were five King Bird-of-paradise (Cicinnurus regius) specimens collected by Alfred Russel Wallace himself. Readers who have actually seen the King Bird-of-paradise, or any of the other species taken by Rist, will rage at learning that he served no prison time and paid only a small fraction of an absurdly inadequate $205,000 fine. This excellent book will provoke pain in ornithologists.

Every chapter of the book is compelling despite the enormity of the story told, and all the more so because Johnson himself is part of the story. A severe case of PTSD resulting from his work with Iraqi refugees necessitated a period of recovery, which led to an interest in fly-fishing. Seeing a brightly colored salmon fly in the tackle box of his guide, Johnson stumbled onto the story of the Tring theft. To research the story, he dove deeply into Wallace's explorations of the biota of the Malay Archipelago. Johnson's telling is rich in detail, including Wallace's ire with an inept preparator: “If he puts up a bird, the head is on one side, there is a great lump of cotton one side of the neck like a wen, the feet are twisted soles uppermost, or something else.” Much more is told of Wallace than is necessary for the story of the theft, but this is all to the good. This book deserves an audience much wider than the puddle of biologists, and they will benefit from understanding the importance of these specimens. The recounting of Wallace's explorations ends with the deposit of his King Birds-of-paradise in the British Museum. From there, the specimens traveled to Tring for safekeeping during World War II. The chapter on Lord Rothschild and his private museum at Tring is shorter but just as engaging. Better still is the subsequent chapter, tracing the feather trade from fashion icon Marie Antoinette to the 1860s, when ornithologist Frank Chapman, over two afternoons on the New York streets, counted 700 feathered hats. The next chapter details how societal pressure, legislation, and World War I ended the feather trade. Ornithologists know this story, no doubt, though details such as the prohibition on the import of ornamental plumage imposed by the Tariff Act of 1922 may be new. Of course, poaching and smuggling followed the bans, but wildlife conservation efforts turned to other taxa. Meanwhile, below the radar, fly-tyers continued their fevered pursuit of feathers. Into this world, now facilitated by the Internet, populated with fly-tying forums and online feather purveyors, stepped Rist, who soon met prominent fly-tyers around the world and learned of the avian riches held by the Tring. Once in England, he visited the collection under false pretenses, posing as a photographer helping a friend who was writing a dissertation on the birds-of-paradise. For ornithologists, these chapters are a tough read, particularly when it becomes clear that the police and the British courts simply do not understand or appreciate the value of the stolen skins.

Johnson reenters the story after the theft, when he becomes obsessed with finding the remaining stolen birds. He meets with fly-tyers around the world, including a student in Norway who idolized Rist and helped sell the stolen goods. He visits Rick Prum at Yale and finds that Prum had compiled screenshots of Rist's website and online offerings before they disappeared; Prum laments that feather trade is ongoing, rampant, and overlooked by law enforcement.

Johnson eventually met and interviewed Rist. If Johnson hoped for an ounce of remorse, he was disappointed. Rist said that if he'd known that Wallace had collected some of the birds, he might have treated them with a little more respect. He opined that the specimens were going to waste because the scientific data had already been extracted and the skins were just collecting dust. He suggested that the Tring's count of missing birds was inaccurate and that others might have stolen some of the missing skins before his own misdeed. Rist did not view himself as a thief. He'd better hope that he never meets an ornithologist in a dark alley.