Researchers investigating the death of an endangered vulture in Spain have found it was poisoned by a veterinary medicine that is banned in other parts of the world.

The cinereous vulture (Aegypius monachus) which is often called a black vulture, was found dead in its nest in September last year at the Boumort Wildland, an ecotourism nature reserve in the Catalan Pyrenees region of north-eastern Spain.

The fledgeling born earlier in the year had only just learnt to fly 10 days earlier and was still dependent upon its parents.

It was found to have ingested the drug diclofenac, a popular anti-inflammatory drug that has been banned as a veterinary medicine in many countries due to the devastating effect its use has caused on carrion bird populations, particularly vultures.

Diclofenac causes severe kidney failure in vultures and has been banned in countries across Asia, but in 2013 Spanish authorities approved its use for livestock purposes despite evidence the decline of Asian vulture populations stopped when it was banned there.

Spain is home to 95 percent of Europe’s declining vulture populations.

The International Union for Conservation of Nature’s Red List of Threatened Species listed the cinereous vulture as threatened since 1988.

Marta Herrero-Villar, 28, is a researcher at the Institute for Game and Wildlife Research (IREC). She told Real Press in an interview that the dead fledgling was discovered due to vultures being monitored and controlled through GPS technology.

A necropsy was performed by the Group for the Rehabilitation of Native Fauna and Habitats (GREFA) to determine its cause of death.

Herrero-Villar explained: “Thanks to an analysis of its stomach contents and a toxic analysis, it was confirmed that it had died of diclofenac poisoning.”

Research published in the journal, Science of The Total Environment, this April by Herrero-Villar and fellow researchers reports the vulture was found to be suffering from severe visceral and articular coagulation caused by drug.

Professor Rafael Mateo, 52, from IREC said it cannot be known how the diclofenac was passed to the vulture, but added: “It must be from the diet, taking carrion from an animal treated with this anti inflammatory.

“Two days before, the same bird was seen alive and apparently in good health during a routinary patrol.”

The animal had been seen feeding in a rubbish tip on the reserve where it lived, but Professor Mateo added: “People in charge of feed that is commonly used on the farms where the carrion comes from said that they did not leave anything there.”

Fortunately, no other animals have died in the area through diclofenac poisoning, including the fledgeling’s parents that were staying close to help it learn to fly.

The professor added: “It was a strange case, as we do not know where it took that poisoned food from, but the main hypothesis is that it came from food given to it in the nest by the parents, but they were not poisoned at all.”

He explained what happens when a cow or pig is treated with diclofenac: “The medicine spreads through its body causing the effect that is meant to do and slowly the levels of the medicine decrease, except in the injection point, where high levels of this medicine remain for days.”

He added: “We believe that it was bad luck the bird ate exactly that part of the injection site with higher levels of diclofenac.”

Conservation groups and researchers have been lobbying for the drug to be banned in Europe, but the European Medicines Agency, despite recognising veterinary diclofenac posed a risk to vultures, decided current livestock management processes were sufficient to prevent it entering the vulture food chain, and only recommended EU member states develop further risk management measures such as regulations and veterinary controls to avoid deadly poisonings.

Professor Mateo acknowledged that following the medicine’s guidelines to prevent an animal treated with it from becoming food for wild fauna would prevent vulture deaths.

But he said: “This is difficult to accomplish in the field, so as a preventive measure – and knowing that there are other non toxic anti inflammatories on the market that are safer for vultures and other animals – the more logical thing would be to ban it for livestock that are commonly the food source of those animals.”

Experts therefore believe the only solution is to ban this medicine in Europe.

He said even a very low dose of diclofenac, between 0.01-0.02 milligrams per one kilo of weight, will have a toxic effect on vultures that is more deadly than classic poisons.

Cinereous vultures grow to one metre long (3.3 feet) with a three-metre (9.8 foot) wingspan and is considered the biggest bird in the Iberian Peninsula and one of the largest on the European continent.

According to Professor Mateo they are crucial to the ecosystem as they dispose of dead animals, controlling the spread of disease by removing pathogens from rotting carcases.

Only 500 individual birds remained in the 80s he said. But now, thanks to different projects, they number around 2,500 breeding couples.

He added that several vulture recovery programmes across Spain are hoping to connect the populations in the Iberian Peninsula with nearby France.

This, it is hoped, will create a European corridor so that vulture numbers can be further strengthened.