Cienciaes.com: Poisoning and decline of the red kite. We spoke with Patricia Mateo Tomás.

2020-07-19 13:01:01

The survival of certain wild species not only depends on the conditions of the natural environment in which they develop, but also on their ability to face the many problems that human beings pose in their unstoppable expansion. Among the species that throughout the last centuries have suffered with special persecution are birds of prey. There were times when anyone who ended up with any “vermin” was rewarded, so qualified because they were considered a competitor of man in the exercise of certain activities such as hunting or livestock. Things have changed a lot, but there is still a long way to go, as Patricia Mateo Tomás, a researcher at the Mixed Biodiversity Research Unit of the University of Oviedo and of the CSICour guest on Talking to Scientists.

Patricia Mateo Tomás is a researcher focused on conservation biology and ecology, with a special interest in scavengers, that is, those animals that feed on the meat of dead prey. Although most of her work is dedicated to vultures, on this occasion, the reason for her participation in the program is the recent publication of a study, published in PNAS, about the red kite (Milvus milvus), a medium-sized bird of prey, reddish in color and with an extraordinarily agile flight that inhabits large regions of Europe. In flight the red kite is unmistakable because it has a deeply forked tail and very visible white spots that occupy a third of the wings at their tips.

The title of the article can be translated as Direct evidence of population decline of a wild vertebrate due to poisoning. It gives a terrible fact, more than 2,600 species of animals around the world are threatened by different types of poisons that are released into the environment.

Poisons of various kinds are used that directly or indirectly affect wildlife. Some are used to combat pests, such as organochlorine insecticides or rodenticides; others, such as lead, are part of the ammunition used in hunting (in a past program of Talking with Scientists we talked about it) and others come from substances for veterinary use used on farm animals. Some of these substances are for legal use and others are prohibited, the latter include poisoned baits used to eliminate predatory species, such as foxes, dogs, wolves and birds of prey, which, as I have said, compete with man for some hunting resources. , ranchers or, to a lesser extent, agricultural.

During the interview, Patricia Mateo tells what we should do if we discover a dead animal on a walk in the countryside and we suspect that it has been poisoned. The main thing is not to touch it, says Patricia, and call the emergency services (“GREFA provides that information here”: When the specialized team arrives at the scene, their way of acting reminds us of what we see in television series of CSI for the human case. The corpse is removed, a chain of custody is established and a forensic team performs the necropsy of the animal to determine the causes of its death. If the animal has been poisoned, tests are carried out to determine the nature of the poison and legal mechanisms are activated.

The published work studies the connection between the detected cases of red kite poisoning (1,075 in total) and the evolution of the populations of this species in 274 locations, formed by squares of land 10 km on each side, along 20 years. The results show that there is a clear relationship between the poisoning of red kites and the decline of their breeding population in Spain, including local extinctions. A decrease in the breeding population has been detected between 31% and 43% during the last two decades.

These studies facilitate the understanding of the effects of poisoning in wildlife and provide essential information to help conserve biodiversity through greater regulatory control of chemical substances.

I invite you to listen to Patricia Matthew Thomasresearcher at the Mixed Biodiversity Research Unit of the University of Oviedoof the CSIC and the Principality of Asturias, at the Center for Functional Ecology, Department of Life Sciences at the University of Coimbra, Portugal, and the Research Institute for Hunting Resources (IRISH) from UCLM.

References:

Patricia Matthew-Thomas, Peter P. Olea, Eva Minguez, Rafael Matthew, and Javier Vinuela. Direct evidence of poison-driven widespread population decline in a wild vertebrate PNAS July 14, 2020 117 (28) 16418-16423; first published June 29, 2020

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