On a trip last year to Panama, I went on an early-morning birding expedition on the famed Pipeline Road, in the hopes of spotting some of the world’s most elusive species. Unfortunately, I discovered in the course of the outing that spotting small birds perched high up in a tropical rainforest can be nearly impossible for a non-expert, and I spent much of my time wondering why I had shown up in the first place. But just as we were heading back to our vehicle, I saw the electric flash of a blue Morpho butterfly for the first time, winging past our party. It was a timely lesson on why humans go to extraordinary lengths to spot animals in the wild: It reminds us that a host of other creatures are making their way across the landscape each day, many of whom are far more impressive than ourselves.

Two recent books — “The Kingdom of Rarities,” by Eric Dinerstein, and “Butterfly People,” by William Leach — explore humans’ quests for nature and their larger implications. While they capture these expeditions with different degrees of success, both writers shed light on why we fixate on species that are so different from us, and what their status in the world says about our own shortcomings.

While “The Kingdom of Rarities” explores two wonky scientific questions — why are certain species rare, and how does this phenomenon inform modern-day conservation? — the book is more of an adventure story than an academic treatise. Dinerstein, who has worked as a World Wildlife Fund scientist for nearly a quarter century, has spent his career traveling to some of the world’s most remote places, taking such good notes that he can relate those encounters in vivid detail. From the greater one-horned rhinoceros to the flamboyant Andean cock-of-the-rock, whose nearly flourescent orange plumage and elaborate song and feather-shaking make it stand out in the Amazon, he has enjoyed nearly unparalleled access to some of the globe’s rarest inhabitants.

Along the way, he has continually asked why some species boast large populations, while others exist in tiny numbers. In some cases the answer is straightforward: Humans have destroyed these animals’ habitat or killed them outright for food or medicinal purposes. Over the past half-century more than 55 percent of Brazil’s Cerrado savanna, where the giant anteater and maned wolf roam, has been cleared for crops or livestock. The Terai elephant-grass ecosystem in lowland Nepal and northern India, once home to thriving populations of tigers and greater one-horned rhinoceroses, is down to just 2 percent of its original range.

But sometimes a species’s rarity stems from other factors, such as its reliance on a specialized habitat. Kirtland’s warblers (named after an Ohio doctor and naturalist, Jared Kirtland) rank as North America’s rarest breeding songbird, largely because they depend on jack pine forests prone to fire disruption. As Dinerstein puts it, “If a shrine to rarity exists, the jack pine woods near Grayling, Michigan, is nature’s Lourdes.” And in the Foja Mountains in Indonesian Papua, a region that is largely off-limits to humans for both political and topographical reasons, golden-mantled tree kangaroos are scarce even though they don’t face the threat of human interlopers because the mountains are so hard to access.


‘The Kingdom of Rarities’ by Eric Dinerstein (Island Press)

Dinerstein’s message is a serious one: We are seeing more populations that are rare largely because of human activities, and this trajectory will continue unabated until humankind starts demonstrating a bit of humility and restraint. But what makes his book a good read is his deft writing and ability to bring his audience to the places he and his scientific colleagues have visited. After a team of researchers takes off from the Foja Mountains in a helicopter, he writes, the “forest would return to its splendid sense of isolation. . . . The bowerbirds would continue to dance around their bowers. Nearby, the male six-wired would shake himself into a joyous blur, and the uninhibited displays of other birds in this paradise would resume without a human audience.”

In “Butterfly People,” Leach analyzes our relationship with the natural world from a historian’s perspective, by looking at 19th-century Americans who devoted their lives to the study of some of world’s most gorgeous insects. His book is impeccably researched, with an astonishing level of detail about these butterfly-obsessed men (and in rare cases, women).

At times, this research is illuminating: It’s fascinating to read about how an immigrant German butterfly enthusiast named Augustus Grote, forced to leave Staten Island and take up residence in Bremen, wrote a friend in 1899 that the mailed gift of a green luna moth’s cocoon eased his homesickness near the end of his life: “A beautiful luna came out today, and I have been watching it for hours and imagining I was back on Staten Island. And his description of the West Virginia laboratory of legendary butterfly collector William Henry Edwardsis priceless. “Edwards converted his own home (basement, porches, clothes closets) and land around it into a nursery, with larvae and pupae stuck on or in virtually every spot — in pots, kegs, barrels, and half-pint jelly glasses with tin tops, and even in his bedroom, where butterflies sometimes pupated, freed by the heat of the fireplaces to fly from room to room.”

But over the course of a long book, this degree of detail becomes overwhelming. Leach dwells at length on the petty infighting among butterfly experts. While these spats do touch on some critical aspects of American society, including the debate over evolution and the question of class, many of them are the sort of tedious feuds that take place in any academic department. Leach writes that Grote’s concerted campaign to discredit another German immigrant, Herman Strecker, in the 1870s and ’80s, changed “the course of American work on butterflies.” But since Strecker went on to publish some of his generation’s seminal works on butterflies, it’s unclear how this extended bout of name-calling changed anything. Leach also explains the logistics of assembling butterfly collections at the 1893 World’s Fair in Chicago (two major collectors declined to put their specimens on display, so visitors mainly perused native species), but it’s unclear why this matters.

Leach is at his best when he describes moments of butterfly discovery, sharing both the insights Americans discovered over the course of a century and the price they paid for that knowledge. Will Doherty, an adventurous young man from Cincinnati who roamed the continent in search of exotic specimens for wealthy Americans and Europeans, died at just 44 after he succumbed to scurvy and dysentery in Nairobi. “Butterflies flew over his grave in Nairobi,” Leach writes, in a fitting coda.

In the end, Dinerstein’s book is the more successful because his central characters — rare creatures that have persisted despite the unlikely odds — prove more compelling than the humans who occupy center stage in “Butterfly People.” In an increasingly crowded planet running short of wild places, it’s more magical to contemplate the animals still running free than the men who dosed them with poison and locked them up behind glass.

Juliet Eilperin , who now covers the White House for The Post, spent nine years as its environmental reporter. She is the author of “Demon Fish: Travels Through the Hidden World of Sharks.”

THE KINGDOM OF RARITIES

By Eric Dinerstein

Island Press. 295 pp. $29.95

BUTTERFLY PEOPLE

An American Encounter with the Beauty of the World

By William Leach

Pantheon. 388 pp. $32.50

Juliet Eilperin is a White House correspondent for The Washington Post, covering domestic and foreign policy as well as the culture of 1600 Pennsylvania Avenue. She is the author of two books—one on sharks, and another on Congress, not to be confused with each other—and has worked for the Post since 1998.