Vultures may not be the most pleasant birds to contemplate, given their motley appearance and association with death, but they serve a vital role in an ecosystem by eating dead flesh.
Throughout India, vulture populations have plummeted to less than 1 percent of what they were a few decades ago, leading to an epidemic of uneaten cattle carcasses and spawning an increase in the number of rats, feral dogs and human rabies cases from dog bites.
But there may be some hope for these much maligned birds: Their decline has slowed, stopped or even reversed in some areas of the Indian subcontinent, according to a paper published today (Feb. 7) in the journal Science.
The birds declined largely because ranchers started giving their cattle an anti-inflammatory drug called diclofenac that the birds ingested when they ate the dead cattle, said paper author and Cambridge researcher Andrew Balmford.
In 2006, following revelations that diclofenac was deadly to the birds, the governments of India, Pakistan and Nepal banned the use of the drug for cattle. Bangladesh followed in 2010, and in May 2012 the four governments reached an "unprecedented political agreement" to prevent unintentional poisoning of vultures from veterinary drugs, Balmford told OurAmazingPlanet.
Many ranchers have adopted an alternative drug that is safe to vultures, Balmford said, but the increase of other drugs is concerning, especially one that's close in structure to diclofenac, Balmford said. Restrictions on these drugs are needed, he added.
Nevertheless, vulture numbers have leveled off in many areas, and increased elsewhere. In India, all three critically endangered species of vultures did not decline from 2007 to 2011, and one species — the oriental white-backed vulture — may have increased slightly, according to the paper.
To help these large raptors rebound, conservationists have established vulture-safe zones. Within them are "vulture restaurants" that provide the birds with diclofenac-free carcasses – "which offer birdwatchers keen to track down vultures a chance to see them," Balmford said. There are also several successful captive breeding colonies, which act as backup populations until reintroducing birds into the wild becomes a possibility, he said. [How Do Vultures Find Dead Stuff?]
"Conservation can work, even in extremely challenging circumstances — in this case an elusive and diffuse threat covering an entire subcontinent — provided there is political will, carefully targeted research and a willingness … to work together," Balmford said.
Balmford elaborates on this theme in a recently published book entitled "Wild Hope."
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.