They are nature’s most opportunistic scavengers, soaring effortlessly in the air on the lookout for their next meal. Mankind has often treated these birds with disgust, but recently it’s been revealed how much we owe them.

Vultures feed on the carcasses of dead animals, helping lessen the chance of disease outbreaks – a fact that was starkly revealed in India over the last few decades. Widespread use of a drug to treat livestock ended up poisoning the birds. “We think we’ve lost somewhere around 40 million birds in the space of two decades, it’s probably the biggest population crash that has ever happened,” says Jemima Parry-Jones, director of the International Centre for Birds of Prey.

In this film, Parry Jones, Dr Ananya Mukherjee of the Saving Asian Vultures from Extinction (Save), Dr M Sanjayan of The Nature Conservancy and environmental economist Pavan Sukhdev reveal what happened next. Without the vultures, carcasses rotted, creating a breeding ground for diseases and leaving a terrible stench. Feral dogs thrived, bringing with them a rise in rabies; India now has the highest number of rabies cases in the world.

Now livestock are being treated with a drug that doesn’t harm vultures, in the hope that the population will recover so that they can return to their vitally important role. As Parry-Jones says: “People tend to think they’re ugly, dirty and smelly, and they’re far from it and they’re absolutely crucial to the environment. They’re the only dustmen in the world who’ve never gone on strike.”

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