Loss of vultures haunts the Indian subcontinent
CHANDIGARH, NAIROBI, LITTLE ROCK––Vultures darkening the sky, trees, and rooftops in growing numbers near slaughterhouses throughout the U.S. South and Midwest in recent years signify as Halloween 2015 approaches that the U.S. has little to fear from ghouls.
Ghouls, in original definition, are grave robbers and scavengers who eat human dead. Research by Texas State University forensic anthropologist Michelle Hamilton demonstrates that vultures typically reduce an exposed human or large animal carcass to bones within hours of finding it.
That leaves little for a ghoul to gnaw.
More dry bones mean fewer zombies
But the dramatic loss of vultures from much of Asia and South Africa during the past few decades means much of the world is having increasing difficulty laying both human and animal dead to peaceful rest.
Vultures, since the dawn of civilization, have flocked around the outskirts of cities, devouring the offal from slaughtering, the remains of diseased animals and others deemed unfit for human consumption, and sometimes human corpses.
Tibetan Buddhists and Parsees, also known as Zoroastrians, have evolved “sky burial” rites which avoid using scarce land and firewood in arid mountain regions by encouraging vultures to eat human dead, instead of burying or cremating the dead.
Dogs, rats, and crows also ubiquitously scavenge among humans, and street pigs in many places, but dispose of large carcasses much less efficiently. The presence of large carcasses meanwhile can attract bigger predator/scavengers who are much more dangerous to humans, work animals, and livestock, among them lions, leopards, tigers, pumas, wolves, bears, and hyenas.
Vultures get what coyotes cannot
Vultures have a less obvious place in the U.S. urban ecology than in Asia and Africa, but occupy essentially the same niche, consuming the remains of poultry, pigs, and cattle left in farm and slaughterhouse dead piles, roadkilled animals, and deer shot but not retrieved by hunters and poachers. While coyotes appear to consume far more dead animals as measured by weight, vultures consume many to which coyotes have no access, for instance on securely fenced livestock industry premises.
Now numbering in the low millions, the U.S. black vulture and turkey vulture populations have been growing at rates of from 1% to 5% per year for more than 30 years, extending their ranges all the while.
Just 60,000 left
Over the same years India has lost about 49 million vultures. The total vulture population of the Indian subcontinent, also including Pakistan, Nepal, Tibet, and Bangladesh, has fallen from circa 60 million to as few as 60,000.
“One species, the Indian white-rumped vulture (Gyps bengalensis), declined by a shocking 99.9 percent,” recounted Scientific American “Extinction Countdown” blogger John R. Platt on September 3, 2015. “The two other Indian species—the Indian vulture (G. indicus) and slender-billed vulture (G. tenuirostris)—each experienced similar declines.”
Producing the first continent-wide population assessment of African vultures in 30 years, published in the journal Conservation Letters, Peregrine Fund director of Africa programs Darcy Ogada in June 2015 reported that the numbers of eight vulture species had declined an average of 62%. Over the most recent three vulture generations, seven of the eight species had declined by 80% or more.
Deaths not mysterious
There is no mystery about why the North American vulture populations are growing, while those of Asia and Africa are at increasing risk of regional extirpation and even extinction.
Like other predators and scavengers, vultures tend to absorb and concentrate in their bodies any toxic substances in the remains of the animals they eat. This problem was recognized much earlier in North America.
Both black and turkey vultures, and the still endangered California condor, declined in the mid-20th century, coinciding with heavy use of the pesticide DDT. While ingesting DDT accumulated in carcasses seldom killed the North American vulture species outright, vultures along with other raptors, such as hawks, owls, and eagles, produced thinner eggs as result of DDT exposure. Thinner eggs meant that far fewer fledglings were hatched successfully.
After the U.S. banned agricultural use of DDT in 1972, black and turkey vultures were among the first raptor species to recover, along with peregrine falcons and bald eagles.
California condors continued to suffer, however, from the effects of ingesting the remains of animals who have been shot by hunters––a food chain accumulation problem which was not identified for decades and has yet to be addressed effectively.
The last 22 California condors then living were trapped in 1982 for captive breeding. Restoration of California condors to the wild began in 1997. The current wild population is at least 232, with about 180 at zoos and breeding centers.
Lead poisoning emerged by 2005 as the leading cause of death among the first reintroduced California condors. California in 2007 banned use of lead shot in eight counties to protect the condors, but a record 21 condors, 9% of the total wild population, were treated for lead poisoning at the Los Angeles Zoo & Botanical Gardens in October 2013.
Alarmed, California governor Jerry Brown on October 11, 2013 endorsed into law a total ban on the use of lead ammunition for hunting––the first adopted by any state, though use of lead ammunition is regulated in at least 30 states.
The California Fish & Game Commission was given until July 1, 2019, to fully enforce the lead ban. Attempts to implement a federal ban on lead shot throughout the entire multi-state range of California condors, also including Arizona, Colorado, Nevada, Oregon, and Utah, have repeatedly been thwarted by opposition from the hunting and gun lobbies.
Meanwhile, about half of the free-flying California condor population have been treated for lead poisoning at least once. Trapped twice a year for blood testing, about a third of the condors show elevated lead levels; about 20% per year require treatment.
Africa & Asia
DDT use was restricted in much of Africa and Asia within a decade of the U.S. ban on agricultural applications, before having much identifiable effect on vultures. Because relatively few people in either Africa or Asia have firearms, lead shot accumulations are not known to to harmed the African and Asian vulture populations either.
But even as California condors recovered from the brink of extinction and were returned to the wild, the Asian and Africa vulture populations collapsed for no immediately evident reason.
Working in partnership with the Peregrine Fund, Washington State University microbiologist J. Lindsay Oaks in January 2003 at last identified the anti-inflammatory drug diclofenac as the cause of the loss over the past decade of more than 95% of the once common Oriental white-backed vulture.
Oaks, who died on January 15, 2011, at age 51, spent the last eight years of his life establishing that diclofenac was also afflicting other vulture species and sounding the alarm.
The source of diclofenac exposure for vultures turned out to be Indian and Pakistani farmers who since the early 1990s have been using over-the-counter and homebrewed medicines containing diclofenac to keep lame oxen, buffalo, and equines on the job pulling carts and plows.
When the animals die, their carcasses are left for scavengers. While residual diclofenac does not seem to harm dogs or jackals, cumulative exposure causes kidney failure in vultures. Slightly more than 11% of the carcasses of working animals tested proved to contain diclofenac.
200 vultures to eat one buffalo
“There can be a population fall of 30% a year if less than one in 200 carcasses available to vultures contain lethal amounts of diclofenac,” Ornithological Society of Pakistan expert Aleem Khan told Agence France-Presse, as the issue heated up. “Two hundred vultures can feed on the carcass of a single big buffalo.”
The Bombay Natural History Society warned in February 2004 that continued sale of diclofenac could cause the extinction of Indian vultures. A similar warning came in June 2004 from Samar Singh, president of the Tourism & Wildlife Society of India.
Based on the Oaks studies and the warnings from organizations known for ecological expertise, the Government of India in May 2006 banned the use and production of diclofenac as a veterinary painkiller through an order of the Drug Controller General. Another readily available drug, meloxicam, which is not lethal to vultures, was recommended as an alternative.
“Not for veterinary use”
But diclofenac products meant for human use remained in production. Vultures rarely encounter residual diclofenac when consuming human remains, the manufacturers argued.
Nonetheless, despite the May 2006 ban, diclofenac was still in widespread distribution. The Drug Controller of India in August 2008 ordered diclofenac makers to label their products with the warning, “Not for veterinary use.”
Nepal, Pakistan, and Bangladesh likewise moved to discourage the use of diclophenac, but while vulture deaths decreased, the vulture population of the Indian subcontinent failed to recover.
Only in mid-September 2015 did India finally ban the production and sale of diclophenac in vials large enough to treat animals bigger than humans.
“70 less-than-legal companies”
The 2006 law “wasn’t enough to stop 70 less-than-legal companies from producing and selling the drug to livestock owners and veterinarians,” explained Scientific American blogger Platt. “Large vials of the human formulation of the anti-inflammatory painkiller remained readily available and widely used by farmers. The new law bans any vial larger than three milliliters, which is enough to treat a person but too small to treat an animal.”
But even if the new Indian law is promptly emulated by Nepal, Pakistan, and Bangladesh, and is enforced, the vultures of the Indian subcontinent may remain at risk from diclophenac.
“Vultures migrate between Asia and the European Union,” wrote Platt. “Diclofenac remains for sale in Spain and Italy,” which host “nearly all of Europe’s estimated 55,000 vultures. Last year the European Medicines Agency advised that the E.U. ban diclofenac,” Platt mentioned, “but to date nothing has happened.”
The British-based Royal Society for the Protection of Birds has since July 2004 funded captive breeding centers for vultures managed by the Bombay Natural History Society in three different regions of northern India: Haryana, Himachal Pradesh, and West Bengal.
Hatching 35 vultures in 2014, the Haryana center, located in the Bir Shikargah wildlife sanctuary, is now planning to experimentally release two vultures who will carry small satellite transmitters. The released vultures are expected to occupy a Vulture Safe Zone covering a 100-kilometer radius along the border of Punjab and Haryana states.
The Egyptian Vulture Conservation Project, initiated by the Environment Society of Oman in 2012, has also enjoyed some success, having recently discovered an estimated 65 to 80 breeding pairs of Egyptian vultures at their primary Oman habitat on Masirah Island. Only a dozen pair were believed to have persisted on Masirah Island in the 1980s.
But African vultures, in addition to suffering from diclofenac exposure, have in the last several years become frequent targets of deliberate attack.
“Hey wildlife cops!”
Explained Salvatore Cardoni for Takepart.com in September 2013, “Hell-bent on offing any witnesses to their deadly operation, elephant [and rhino] poachers have begun killing vultures en masse by lacing the discarded pachyderm bodies with poison pills. Why, you ask? Because circling, squawking vultures are the savanna equivalent of a screaming coal mine canary: ‘Hey Wildlife Cops, a Bunch of Elephants Were Just Murdered Right Below Us, And If You Hurry, the Poachers Might Still Be Catchable! Go! Go! Go!’”
600 vultures poisoned
Cardoni wrote about six weeks after as many as 600 vultures were poisoned to death at a single elephant carcass in Botswana National Park, Namibia. The International Union for the Conservation of Nature had recorded similar incidents in Botswana proper, Tanzania, Mozambique, and Zimbabwe.
The only way to combat vulture poisoning by elephant poachers is to more effectively combat elephant and rhino poaching. Across Africa, more than 30,000 elephants and 2,000 rhinos were poached in 2014, including a record 1,215 rhino in the nation of South Africa. Poaching is believed to have reduced the African elephant population by more than 60% in 10 years, while barely 29,000 rhino remain, of all species and subspecies combined.
Hanging the dead
Meanwhile in the U.S., USDA Wildlife Services has resorted to hanging dead vultures as a warning to unwelcome concentrations of their kin.
“Vultures have an aversion to the dead of their own kind,” U.S. Army Corps of Engineers spokesperson Laurie Driver explained to Arkansas Democrat-Gazette reporter Bill Bowden in June 2015, crediting the Halloween-ish “hang ‘em high” approach with reducing the number of vultures roosting on or near Bull Shoals Dam, near Little Rock, from about 300 to 40 in only a week.
Hanging up dead vultures has also been done recently in Bridgewater, New Jersey, and six other New Jersey towns; Jacksonville, North Carolina; Jedburg, South Carolina; and Salisbury and Staunton, Virginia.
Though this might deter vultures, it seems as likely to bait in ghouls.