First case of mortality associated with pentobarbital intoxication in a bearded vulture

    The case highlights the risk posed by the carcasses of domestic animals euthanized with veterinary pharmaceuticals such as pentobarbital for the conservation of avian scavengers, including the bearded vulture, considered endangered in Europe.

    Livestock carcasses available in the field are an essential food resource for avian scavengers. However, they are also their main source of exposure to veterinary pharmaceuticals, which could compromise their survival. An example is found in barbiturates, used for the euthanasia of domestic animals. Previous studies have already shown that barbiturates cause lethal poisoning in different species of obligate and facultative scavenger birds and mammals when they feed on these euthanized animals, with vultures being especially affected.

    Scientists from the Research Group in Wildlife Toxicology and the Research Group in Health and Biotechnology (SaBio) of the Instituto de Investigación en Recursos Cinegéticos (IREC – CSIC, UCLM, JCCM), in collaboration with the Foundation for the Conservation of the Bearded Vulture (FCQ), have described the first case of mortality associated with pentobarbital intoxication in a bearded vulture (Gypaetus barbatus) .

    Although its carcass was found with electrocution injuries next to a power line, toxicology analysis also showed that the animal had been exposed to pentobarbital at a dose that could have caused sedation, increasing the risk of trauma or electrocution.

    First case of mortality in bearded vultures (Gypaetus barbatus) associated with pentobarbital poisoning


    The bearded vulture is classified as Near Threatened (NT) worldwide, but in Europe it reaches the category of Endangered (EN), so the risk of this avian scavenger suffering intoxication from veterinary drugs such as pentobarbital is a factor of great concern. In addition, Spain is an important bastion for the conservation of the bearded vulture, with at least 252 individuals recorded in 2018, mainly in the northeast of Spain, representing almost 60% of the European population of the species (Photo: Pilar Oliva-Vidal).

    Despite the bearded vulture feeds mainly on bones of ungulates, this species may also be exposed to veterinary pharmaceuticals with a high volume of distribution and the ability to reach the bone marrow, such as pentobarbital.

    In this study, the scientists describe the new threat that this veterinary pharmaceutical pose to bearded vultures in northern Spain, precisely where the highest prevalence of intoxication by this euthanasia agent in scavenger fauna species had previously been detected. On the other hand, the researchers underline the need to implement mitigation measures and control strategies to prevent veterinary pharmaceuticals from entering the food chain of scavenger birds, becoming an additional risk for endangered species.

    The scientific publication of this research is available at: