For all their importance to the smooth running of nature’s threshing machine, vultures themselves are being mowed under at an alarming rate. Sixteen of the 23 vulture species are listed by the International Union for the Conservation of Nature as threatened or endangered, four of them critically.
Among the biggest menaces to vultures today, experts said, is poisoning, both incidental and intentional. Wherever there is conflict between people and carnivores, vultures often end up as collateral damage. The standard scenario is this: Farmers who lose livestock to predators like lions or hyenas will fight back by setting out a carcass laced with pesticides. But while the lion may return and take the bait, Dr. Kendall said, “30, 40, 50 vultures will come in and also die.”
Or many more: In the last few years, single poisoned carcasses have led to the deaths of over 1,000 hooded vultures in Guinea-Bissau, and close to 800 in Botswana. In Mendoza, Argentina, in 2018, 34 Andean condors died after feeding on a poisoned carcass. “This could be 10 percent of the condor population in that area,” said Sergio Lambertucci, who studies condors at Argentine Research Council and the National University of Comahue.
By far the most devastating case of accidental vulture slaughter took place in India in the 1990s, when tens of millions of vultures died after feeding on the carcasses of cattle that had been treated with diclofenac, an anti-inflammatory drug. By the time experts figured out what was happening, the Indian vulture population had collapsed by more than 99 percent. Hard-hit species like the white-rumped, long-billed and slender-billed vultures may never recover.
Scientists and conservationists are working fiercely to stem vulture declines, through community outreach and education; negotiating with government officials, farmers, ranchers, anybody who lives in the vicinity of vultures and has clout; basic research and captive breeding programs to keep vulture stocks going. Captive-bred animals are rarely released into their natural environment, but Ms. Kottyan, of the Maryland Zoo, has some hope for the descendants of Shredder and Kenya.
“If we can tackle all the problems that lappet-faced vultures now face in the wild,” she said, “maybe we can get some of our birds back out there, too.”