The Moustached Kingfisher, photographed for the first time.

For Christopher Filardi of the American Museum of Natural History, there is nothing like the thrill of finding a mysterious species. Such animals live at the intersection of myth and biology - tantalizing researchers with the prospect that they may be real, but eluding trustworthy documentation and closer study. Indeed, last month, Filardi waxed poetic on the hunt for the invisible beasts that nonetheless walk among us."We search for them in earnest but they are seemingly beyond detection except by proxy and story," he wrote. "They are ghosts, until they reveal themselves in a thrilling moment of clarity and then they are gone again. Maybe for another day, maybe a year, maybe a century."Filardi was moved because, trolling what he called "the remote highlands" of Guadalcanal in the Solomon Islands, he had found a bird he had searched more than two decades for: the moustached kingfisher."Described by a single female specimen in the 1920s, two more females brought to collectors by local hunters in the early 1950s, and only glimpsed in the wild once," he wrote. "Scientists have never observed a male. Its voice and habits are poorly known. Given its history of eluding detection, realistic hopes of finding the bird were slim."Yet, defying the odds, Filardi did just that.After setting mist nets across the forest, he and his team secured a male specimen with a "magnificent all-blue back" and a bright orange face. The discovery brought quite the declaration - "Oh my god, the kingfisher" - and led Filardi to liken it to "a creature of myth come to life." And then, Filardi killed it - or, in the parlance of scientists, "collected" it.This was not trophy hunting - but outrage ensued."Of course, 'collect' means killed, a lame attempt to sanitize the totally unnecessary killing of this remarkable sentient being," Marc Bekoff, professor emeritus of ecology and evolutionary biology at the University of Colorado, wrote in the Huffington Post. "When will the killing of other animals stop? We need to give this question serious consideration because far too much research and conservation biology is far too bloody and does not need to be."The controversy led Audubon - which had previously published a piece innocently titled "Moustached Kingfisher Photographed for First Time" - to add quite the editor's note."This story has been updated to clarify that the bird was euthanized and the specimen collected," Audubon wrote. A researcher on Filardi's team, it added, "told Audubon that they assessed the state of the population and the state of the habitat, and concluded it was substantial and healthy enough that taking the specimen - the only male ever observed by science - would not affect the population's success."Still, to some, finding something only to kill it didn't even seem to rise to the level of irony. It just seemed twisted."These were, indeed, the first-ever photos of the male moustached kingfisher alive," by Chris Matyszczyk wrote at CNET. "It didn't live much longer."Filardi was also compelled to respond in an op-ed for Audubon: "Why I Collected a Moustached Kingfisher.""I have spent time in remote, and not so remote, forests of the Solomon Islands across nearly 20 years," he wrote. "I have watched whole populations of birds decline and disappear in the wake of poorly managed logging operations and, more recently mining. On this trip, the real discovery was not finding an individual Moustached Kingfisher, but discovering that the world this species inhabits is still thriving in a rich and timeless way."Filardi stressed that, among Guadalcanal locals, the bird is known to be "unremarkably common." He explained how he and his team made the decision - "neither an easy decision nor one made in the spur of the moment" - to collect the bird with reference to "standard practice for field biologists." And he said that killing one kingfisher might help save them all."I have come to know, through firsthand experience, how specimens and other artifacts in museums can over time become sacred," he wrote. ". . . I have watched sparks ignite in the eyes of Pacific Islanders holding specimens of extinct species doomed by habitat loss, invasive species or disease. I have watched my friends, my colleagues - those I work both for and with - go home and out into the world and make a difference. These moments drive my work. Through a vision shared with my Solomon Island mentors . . . the Moustached Kingfisher I collected is a symbol of hope and a purveyor of possibility, not a record of loss."But - was he right?Wildlife experts have been debating that question for more than 100 years - ever since they first noticed that the colorful and charismatic species they wanted to document had begun to vanish. The pro-collection camp says that the practice requires the death of only a few individuals and may provide knowledge that helps to ensure the survival of the overall species. The "voucher specimen" - a representative specimen used for studies - is considered the gold standard for documenting a species' presence: It's the most definitive way to confirm that an animal exists and serves as the basis for all kinds of research on its health and habitat.But opponents point out that history is littered with the stuffed and mounted carcasses of animals that were the last of their kind, bagged by overzealous collectors who didn't stop to consider the cost of the kill.In collecting's heyday, bagging a rare species was a point of pride for naturalists, and wealthy wildlife lovers amassed taxidermied animals the way another person might accumulate art. Famous scientists like Charles Darwin and Alfred Russel Wallace collected and preserved hundreds, thousands, even tens of thousands of specimens - most of which served a vital role in making new species known to science. But collectors, who traveled to the world's most remote regions in search of as-yet-unknown animals, also had an Indiana Jones-like swagger.Competition to find something first was fierce, and institutions vying for new and exotic specimens meant that dozens of researchers would go tramping up mountains and into jungles to kill the same animal.Among the most famous victims of this is the Great Auk, a now-extinct North Atlantic bird with a penguin's tuxedo-like plumage and ungainly waddle (but not much of its DNA - Auks are only distantly related to their Southern Hemisphere cousins).The species was already teetering on the brink when naturalists and museums took an interest in it in the 19th century. Climate change during the Northern Hemisphere's several-century cool spell known as the "Little Ice Age" had decimated the population. Humans then finished the job. The birds stood nearly three feet tall and sported thick, plumage, making them a valuable food source and even more valuable commercial product. And its clumsiness on land (and inability to fly) made it an easy target for hunters.Paradoxically, it was the Great Auk's sudden rarity that made scientists so eager to kill them. According to the Smithsonian, the Great Auk's classification as endangered in 1775 led to increased demand for specimens - a single bird could be sold for $16 in the early 1800s, a full year's wages. No longer hunted for its meat and down, the Great Auk and its eggs became a target for their scientific value. In 1844, a group of fishermen caught two of the birds on a remote island off the Icelandic coast. They were sold to a chemist in Reykjavik, who stuffed and mounted the birds, then preserved their eyes and internal organs like pickles in jars of alcohol. No one on record has seen one of the huge, black-and-white birds since.This anecdote was cited in a controversial article for the journal Science last spring. Under the headline, "Avoiding (Re)extinction," four biologists cautioned against collection of rare species. The practice "can magnify the extinction risk for small and often isolated populations," the authors wrote, encouraging alternative forms of documentation like DNA samples, photographs and sound recordings.Ben Minteer, an ethicist at Arizona State University's school of life sciences and the lead author of the article, told NPR that he doesn't think scientific collecting is a leading driver of extinction - there would have to be millions of researchers bagging birds every day to match the job that climate change, habitat destruction and overexploitation have done on at-risk populations. But in cases where a species is near extinction, a few deaths in the name of science can have a major impact on the overall population, he said, and stricter codes on what species can be collected are necessary."It's one thing for a community to say, 'Look, we have a code of ethics, we abide by it, no responsible biologist would ever do this,'" he said in 2014. "You know, we think that those are all good things and good statements but it's harder to actually create a sort of ethical culture in the field when no one's looking - when no one's watching."The article raised the hackles of many in the scientific community. In the next month's issue of Science, more than 100 biologists signed multiple response letters in defense of collecting."Our goal should be to document biodiversity and rigorously as possible through carefully planned collections so that it can be effectively preserved and understood," one letter read. "Specimens from such collections and their associated data are essential for making informed decisions about management and conservation now and in the future."The letter pointed out that species collections can lead to unexpected discoveries - famously, a discovery that recent eggshells were thinner than older ones at a British museum alerted Europeans to the dangers of DDT in the 1960s - and that scientists have come a long way from the indiscriminate collecting practices of the 19th century, supporters of collecting argue. Now, researchers must get approval and permits to collect before they even go out in the field. Each request is evaluated based on the distinctiveness of the find and rarity of the species. If a species is unknown to science, or if there aren't other good museum specimens in existence, then killing and preserving an individual might be the best way to learn more about it.This, Filardi argues, was the case with the moustached kingfisher. Until now, there were only three specimens in existence, and all of them were female. A modern, male sample will improve scientists' understanding of the species and its changing environment, he said.It might also galvanize support for efforts to protect the kingfisher's island home. Speaking to Scientific American, Filardi said that mining and logging threatens the mountains where the elusive blue-and-yellow birds live, as does climate change. "We still have the potential to steward this big sky island and preserve all of its richness," he said, but only if conservationists and local governments work out ways to negotiate those threats.For years, Western scientists have referred to the kingfisher as a "ghost" species because they've never been able to spot it. But Filardi estimated that thousands of pairs remain in Guadalcanal. The species is not dead yet, he said. It won't become a ghost unless we let it.© 2015 The Washington Post