Scott Weidensaul is a nature writer, but beyond that, he defies categorization. His books are informed by a personal voice, yet they also offer explanations for lay audiences of scientific — particularly ornithological — research by someone who earned his credentials by long years in the field banding birds and studying their life histories. He puts it all together in an evocative prose style that raises his work out of its generic limitations. His last book, Living on the Wind: Across the Hemisphere with Migratory Birds, was short-listed for the Pulitzer Prize.

Weidensaul has just published The Ghost with Trembling Wings: Science, Wishful Thinking, and the Search for Lost Species, a much quirkier book that's even more interesting for its quirks. He recounts the search for animals that probably never existed — like the remnant dinosaur famously resident in that lake in Scotland, or feral panthers prowling the moors of England. "We paint the blank spots on maps with our deepest fears and secret longings," he writes, "and today we still grasp at straws, unwilling to admit that we've wrung most of the mystery out of the world."

But Weidensaul is primarily interested in stories about attempts to rescue species that border on extinction. A memorable chapter details efforts to save the black-footed ferret, a graceful weasel-like creature that lives with and feeds on prairie dogs. As the prairie dogs were largely eliminated to make way for cattle, the ferrets all but disappeared. Several times we thought they were extinct, and then small populations were discovered in remote areas. Our first efforts to save them seemed to do more harm than good, but recently, Weidensaul tells us, we've gotten better at it, reintroducing ferrets bred in captivity back into the wild.

My favorite parts of this book are the chapters where Weidensaul goes into the forests and the mountains looking for animals that have just recently been called extinct. He goes into the swamps of Louisiana looking for ivory-billed woodpeckers after a reputable observer claims to have seen a pair of those extraordinary birds thought vanished for nearly half a century. He wanders around western Tasmania, looking for the thylacine — a wolflike marsupial — following the hunch of an aging Tasmanian scientist. And in the best chapter of all, entitled "Sweet Bees Ate Our Earwax," he fights off the insects of western Brazil to look for the cone-billed tanager, a bird seen only once more than sixty years ago. He doesn't find it, but the search has its own meaning: "I'd been following the faint track of lost animals for nearly two years, immersing myself in many exotic landscapes like this one — a pursuit that forced me to look at the world in a new and more auspicious way, alive to hope, however tentative, in the face of great and grievous biological loss."

Scott Weidensaul reads from The Ghost with Trembling Wings at Shaman Drum Bookshop on Monday, June 17.