The RSPB has reported the results of two studies which revealed that a greater diversity of birds of prey, including some eagles, are killed eating carrion contaminated with diclofenac.
The RSPB says that these findings strengthen the case of banning the use of veterinary diclofenac in livestock across Europe, including Spain and Italy where the drug has already been approved.
In the first paper1, published in the journal Bird Conservation International, scientists present results of tests carried out on two steppe eagles found dead at a cattle carcass dump in Rajasthan, India. Both birds had diclofenac residue in their tissues and exhibited the same clinical signs of kidney failure as seen in Gyps vultures experimentally given diclofenac.
Steppe eagles are closely related to the golden eagles found in the UK, the vulnerable Spanish imperial eagle and other globally vulnerable or declining Eurasian eagles. Scientists now fear that all species in this genus, known as Aquila, are susceptible to diclofenac. With fourteen species of Aquila eagle distributed across Asia, Africa, Australia, Europe and North America, this means that diclofenac poisoning should now be considered largely a global problem.
Dr Toby Galligan, RSPB conservation scientist and one of the authors of the paper, said: "We have known for some time that diclofenac is toxic to Gyps vultures, including the Eurasian griffon vulture, but we now know it is toxic to an Aquila eagle too. This suggests that the drug is fatal to a greater number of birds of prey in Asia, Europe and around the world. We had suspected as much from observed declines in non-Gyps vultures in Asia, but this study confirms our worst fears."
In another paper2, published in Bird Conservation International, Dr Galligan led an examination of recent population trends in Egyptian and red-headed vultures in India. That study shows population declines of similar timing and scale as the declines observed in Gyps vultures, providing indirect evidence that these species have been impacted by diclofenac as well.
After years of campaigning by conservationists, the governments of Bangladesh, India, Nepal, and Pakistan banned veterinary formulations of diclofenac between 2006 and 2010. Recently, experts have recorded a slowing of Gyps vulture declines as a result of the bans. However, formulations of diclofenac intended for use in humans are still widely available and illegally used to treat livestock, the carcasses of which are the main food source for vultures in South Asia. It was announced in March that veterinary diclofenac had been authorised for manufacture and use in Italy and Spain and had been distributed to other European countries. Since then, a coalition of organisations including the Vulture Conservation Foundation, the RSPB and BirdLife International have been campaigning for this decision to be reversed.
Dr Galligan continued: "In light of recent developments in Europe, our findings take on an even more worrying meaning. All of Europe's charismatic Aquila eagles, like the Spanish imperial eagle and, closer to home, the golden eagle, are opportunistic scavengers and therefore could be at risk of diclofenac poisoning. As we have seen in South Asia, wherever free-ranging livestock are treated with diclofenac, population declines in vultures and eagles can occur. The European Commission needs to recognise this problem and impose a continent-wide ban on veterinary diclofenac before it can impact on our birds."
Last week, the Veterinary Medicines Directorate (VMD) announced measures against the drug.
In a statement the VMD said: "The UK's Veterinary Medicines Directorate is taking the issue of diclofenac's risks to vulture populations seriously. As a precautionary measure the VMD will not approve any requests from vets to import products containing diclofenac. Furthermore, the VMD has agreed not to issue any export certificates which name diclofenac-containing products in the list of products to be exported."
Sacha Cleminson, Head of International Biodiversity Policy at the RSPB, said: "The announcement from the Veterinary Medicines Directorate is a welcome signal to Europe that the UK is taking the issue seriously. This new evidence underlines the need for a ban across Europe, and ultimately beyond."
References
Have population declines in Egyptian Vulture and Red-headed Vulture in India slowed since the 2006 ban on veterinary diclofenac? Toby H. Galligan et al. Bird Conservation International Online. 1st April 2014.
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