The Telegraph, by Will Brown: A catastrophic decline of vulture populations in Africa and Asia is causing alarm among researchers, who fear that a “cascade” effect could lead to the spread of deadly old and new diseases, including plague, anthrax, and rabies.
For thousands of years, the birds have been synonymous with death and gluttony. “Where the corpse is, vultures will gather,” Jesus is quoted as saying in Matthew 24. But in reality, the birds serve us in ways that we are only just beginning to understand – helping to keep ecosystems and pathogens in check.
If the lion is the king of the savannah, the vulture is the hardworking, unsung grounds keeper. A flock of vultures can wipe a dead antelope clean in about 20 minutes, stopping the carcass from turning into a toxic soup leaking into water sources. Maggots and bacteria are the only things more effective at disposing of dead meat.
The birds’ digestive systems are thought to be tough enough to stop bacterial colonies of the plague, anthrax and botulism in their tracks. Some researchers believe vultures indirectly keep rabies infections in check by depriving rats and feral dogs of bountiful food. Certain species may even help disinfect the ground near carcasses with their highly acidic excrement.
But now, many vultures and other raptor species are diving beak first into the abyss. In the 1990s, vulture populations on the Indian subcontinent plummeted by about 99 per cent. Seven out of eleven of the species found in Africa are now on the verge of extinction.
“Vultures and other medium to large raptor species are probably the most threatened group of vertebrates on the planet,” said Shiv Kapila, director of the Naivasha Raptor Centre, 60 miles from the Kenyan capital. “The rate of decline is staggering. We still don’t know nearly enough about what all this means. We’re working on borrowed time.”
“If you screw up natural equilibriums that have developed over tens of millions of years, you can get what we call a trophic cascade effect,” he added, reaching up and giving Yusef, a seven-year-old Rüppell’s vulture with a broken wing, a helping hand down from the ledge.
“If you get rid of a hugely important component of an ecosystem – like a vulture which hoovers up dead meat – diseases can proliferate because they’re not being kept in check,” Mr. Kapila said.
Because of the centuries of bad press, experts say that African vultures have never been a well-funded research area like elephants or rhinos. But work by a handful of naturalists in Kenya offers clues about the consequences of their decline.
A paper published earlier this year found that, over the last 40 years, vulture numbers have fallen by 88 per cent in Kenya, Some birds of prey – like the augur buzzard and long-crested eagle – also plummeted by more than 90 per cent.
There are several causes. Some of the vultures die indirectly, by villagers poisoning a carcass to stop a lion from attacking their cattle. Some are killed for religious reasons or from the rapid development of their habitats. Others are directly targeted by poachers in trying to rid the area of the tell-tale sign of their crime for rangers – the dark circling flock above.
Shock and poison
One major new concern is electrocution. Kenya is rapidly upgrading its electricity network, replacing old wooden power poles with concrete ones with supportive steel rods running through them. Conservationists say that the poles’ shoddy construction and insulation, which would not be allowed in richer parts of the world, kill thousands of raptors every year.
“Many birds won’t just die on the spot after being electrocuted,” said Mr. Kapila. “They’ll fly away after the shock. Maybe they’ll hide under a bush so we can’t find them. It’s a slow, protracted, agonizing death. Their limbs will atrophy, and will eventually fall off.”
Meanwhile in South Asia, the vulture population crashed from an estimated 40m in the 1980s to roughly 19,000 in 2017 because of diclofenac – a widely used drug to treat pain and inflammation in cattle – which overloaded the birds’ kidneys after eating the carcass.
This had some surprising knock-on effects. Historically, the Parsi religious community have placed their dead on a ‘Tower of Silence’ in a plush neighbourhood in Mumbai and let swarming vultures devour their friends and relatives.
Cremations and burials are sacrilegious for Parsis, but the vultures allow the souls to reach heaven. Because there are not enough vultures to go around, high Parsi priests erected solar panels around the Tower to concentrate the sun’s rays on the bodies, speeding up the natural decomposition process.
The direct health consequences are harder to nail down because of a lack of research. A landmark paper in 2012 by Darcy Ogada, Africa Director at The Peregrine Fund, found that there would be more scavenging mammals like feral dogs and hyenas at a carcass when vultures were not present.
Because of the close contact, these scavengers were far more likely to spread diseases. While vultures fly far away to a cliff or tree top, scavenger mammals are far more likely to live around human communities.
“It’s fiendishly complicated, and we’re still trying to untangle the actual consequences…for disease ecology,” said Campbell Murn, a leading international raptor expert at the Hawk Conservancy Trust in Hampshire.
“Vultures eat more dead stuff than almost everything else put together. They do the heavy lifting, not lions or hyenas. And it is likely that vultures potentially limit the spread of some diseases by getting rid of carcasses, but the actual role they play in doing this is still unclear.”
“They’re at the top of the food pyramid,” Mr. Murn added. “They’re really good indicators of what’s happening in the ecosystem at large. I think biodiversity is a bit like a blanket that keeps humans warm. Each thread is like a species or interaction between species. You can take one out and you’ll still have a blanket. But eventually, that blanket is going to fall to pieces.”
Mr. Kapila worries about what vulture decline might mean for the spread of new zoonotic diseases, like Ebola, which spillover from the natural world to humans.
“Zoonotic diseases have really begun to multiply in the last 50 years. This is because we have begun invading forests and eating bushmeat, putting us in increasingly closer proximity to wildlife, and generally upending finely balanced micro ecosystems inside these larger systems,” he said.
“Vultures, the natural disposers and controllers of these pathogens, are increasingly threatened, meaning they are less effective at keeping everything in check. What does this mean going forward? When you combine this with the world’s skyrocketing population, I think it’s a terrifying trend.”
Mr. Kapila is not alone in his concern. This week, the World Health Organization warned that Africa is facing a growing risk of outbreaks of diseases that spread from animals to people.
It found zoonotic outbreaks have increased by more than 60 per cent over the last10 years compared to the previous decade, with a large spike recorded since 2019, largely because of rapid population growth and encroachment on wildlife habitats.
Some say it is not too late to turn the tide, pointing to some extraordinary conservation successes in the richer world. Europeans and North Americans have brought many of their raptor species back from the brink. Last year, an Egyptian vulture was seen in the UK for the first time since 1868.
Elsewhere, private donors are having an impact. Mohamed bin Zayed, the ruler of the United Arab Emirates, is paying for thousands of miles of badly made Chinese electricity pylons to be retrofitted in Mongolia. It is thought that some 4,000 endangered Saker falcons were being killed on the lines every year.
Still, the prospects for vultures and raptors across much of the world are grim. “The actual consequences of losing vultures are still largely unknown, for us, for other animals and for the ecosystems that support us,” said Mr. Murn. “We need to stop vultures disappearing because we don’t know what comes next if they go.”
Prophetic Link:
“The time is near when the whole animal creation will groan under the disease which curses our earth because of the iniquity of the fallen race.” Manuscript Releases, Vol. 21, page 286.6.
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