New letter in Science reminds governments of their obligations to regulate vet drugs more effectively ahead of the 2026 CoP of the Convention on Migratory Species
The letter “Vulture conservation requires NSAID regulation”, published on 4 September in the journal Science, 30 years on from the beginning of the devastating effect of the NSAID diclofenac on vulture populations in South Asia, highlights how regulation of the veterinary use of non-steroidal anti-inflammatory drugs (NSAIDs) toxic to vultures remains inadequate.
Widespread use of diclofenac to treat cattle left three previously abundant vulture species red-listed by IUCN in their most extreme category of risk of global extinction, short of extinction in the wild itself, because the drug causes kidney failure, rapidly followed by death, when vultures feed on the carcass of a recently-treated animal. Despite the discovery and thorough documentation of this problem in 2004, a key problem is that no vulture range state has yet introduced an effective system for quickly withdrawing veterinary products shown to be toxic to vultures and no vulture range state requires data on safety to vultures in advance of licensing veterinary NSAIDs.
In the 20 years since the diclofenac problem was identified, only Nepal has sufficiently controlled the use of such drugs to allow vulture populations to recover.
Although the use of diclofenac has declined in most countries, it is still used illegally in many areas and, even where declines in its use have occurred, a new problem is that several other toxic NSAIDs, including flunixin, ketoprofen, nimesulide, and aceclofenac, have partly replaced it. There have been welcome recent steps for some of these other toxic drugs being banned, but this has typically occurred more than ten years after convincing evidence of their toxicity was published. The drugs are still widely available in parts of South Asia and Europe.
In their letter, authors Dr Antoni Margalida and Professor Rhys Green point out that a recent Convention on Migratory Species (CMS) Resolution (Resolution 11:15) has chalked out a better way forward by calling for much more effective action by governments to regulate toxic veterinary NSAIDs- both before and after they are approved for legal use. The next CMS Conference of the Parties in March 2026 gives governments a real opportunity to demonstrate that they are responding to this call, which is urgent because NSAIDs still threaten vulture populations in European and Asian countries and many populations are already very depleted relative to former levels – for one species by a factor of about one thousand.
Co-author Dr Antoni Margalida of the Spanish National Research Council (CSIC) points out with some frustration “It was disappointing that diclofenac, the main killer of vultures across Asia, was then licensed in several European countries, including Spain where most European vultures live. Although measures intended to prevent exposure are in place there, they are not preventing toxic-NSAIDs like diclofenac and flunixin from entering the vultures’ food-chain.”
Co-author Professor Rhys Green of the University of Cambridge and RSPB says “Just two NSAIDs (meloxicam and tolfenamic acid) have so far been found to be safe for vultures, but in neither case did the pharmaceutical industry fund the testing and no government process in any vulture range state yet requires them to do so before approval for their product is first granted or allowed to continue.”
Umberto Gallo-Orsi of the Raptors MoU of CMS adds: “When equally affordable alternative veterinary drugs like meloxicam and tolfenamic acid are widely available, and the scientific evidence of just how lethal some NSAIDs are to vultures, it seems clear that actions proposed in the CMS Resolution need wider implementation. Several South Asian countries have recently made useful decisions about banning specific NSAIDs, but more action is needed.”
Mr Vinayagan Dharmarajah, Regional Director of BirdLife International in Asia said “We hope that this letter sends an important message ahead of the CMS March 2026 Conference of the Parties (COP). Parties to CMS include the vulture range states India, Pakistan, Bangladesh, Spain, and Italy. These governments, and others that host vulture populations can demonstrate what has been done so far, but should take further action before the next CMS COP to better regulate these problematic drugs. Making current bans more effective and testing which others are toxic and which are safe are among the main actions needed if we are serious about securing the future role of vulture populations.”
Mr Alex McWilliam, Regional Coordinator, Species and Habitats, IUCN Asia, added “Recognising that governments and partners in some countries have made important progress towards improving management of NSAIDs that devastate vulture populations, it is important to step up efforts to systematically address the issue and look to adopt safe alternatives. This, combined with increased efforts on the ground to conserve and recover vulture populations, will ensure a future for these species and their critical role in the health of ecosystems”.
Compiled by Chris Bowden, SAVE Advisor
Link to Science article: Science | AAAS
CMS Resolution 11.15 (Rev.COP13); https://www.cms.int/raptors/en/page/non-steroidal-anti-inflammatory-drugs-and-vultures.
