A recently approved veterinary drug has been confirmed as the cause of death of a vulture in Spain. Conservationists say the incident could be the tip of an iceberg, and warn that the drug could wipe out many of Europe’s vultures as well as harming related species, including golden eagles.
The anti-inflammatory agent diclofenac has already been banned in India, Pakistan, Nepal and Bangladesh after it was found to kill vultures that ate the carcasses of cattle treated with the drug. Tens of millions of vultures are believed to have died in this way with some species declining by a staggering 99.9% in parts of south Asia.
Nevertheless diclofenac was approved in Spain and other European nations because farmers, drug companies and regulators argued that cattle carcasses were disposed of differently in Europe than in India. This meant vultures would not be able to eat meat tainted with diclofenac.
“That claim has now been shown to be wrong,” said John Mallord, of the Royal Society for the Protection of Birds. “A young cinereous vulture in the Boumort National Hunting Reserve in Spain has been confirmed to have died of diclofenac poisoning.”
“This is a hugely worrying development. You can have several vultures feeding on a single cattle carcass, and if it is contaminated with the drug, you will kill them all just from a single feeding. This has probably been happening for some time, with many other vultures having died.”
Europe has four species of vulture: bearded, cinereous, Egyptian and griffon vultures. Recent research has also found that diclofenac not only kills vultures but is fatal to eagles of the genus Aquila whose members include the golden eagle and the Spanish imperial eagle. There are only about 300 pairs of imperial Spanish eagles left.
“The evidence found in Spain sadly confirms what we have been warning about for almost a decade,” said Ivan Ramirez, of the conservation group BirdLife International. “Vultures are dying from veterinary diclofenac poisoning and this could already be affecting population trends. It is absurd to keep insisting on licensing a drug that kills threatened species when there are plenty of other safe and cheap alternatives in Europe.”
In south Asia, the species of vulture that were worst-affected by the introduction of diclofenac in the late 20th century included long-billed, slender-billed and oriental white-rumped vultures. The white-rumped was once thought to be the most abundant large bird of prey in the world with a population of many millions of birds. By 2016, their numbers had dropped to around 10,000.
And these devastating declines had major ecological impacts. In India, Nepal and Bangladesh, dead cattle were left to rot without vultures to consume their flesh. Packs of feral dogs grew to fill the ecological gap and the risk of rabies also rose as a consequence, health experts said. Similarly, populations of crows increased, which raised the risk of infections being passed from them to poultry and humans.
As a result of this avian attrition, the use of diclofenac, as an anti-inflammatory treatment for livestock, was outlawed in India in 2006 (though it is still sold in small doses as an anti-inflammatory agent and painkiller for humans). Nevertheless, despite its past ecological impacts, it was approved for veterinary use in Spain and Italy several years ago.
“The vast majority of Europe’s vultures are found in Spain,” added Mallord. “We were told there was no threat to them from diclofenac. Now we have found clear evidence that shows this is not the case. Given that there are perfectly good, safe alternatives to the drug that could be used on cattle, it is time that the veterinary use of diclofenac is banned in Europe as a matter of urgency,” he added.