An international team has calculated for the first time the impact of lead poisoning in birds of prey, which feed on prey killed or injured by lead shot, in 13 European countries. The results show a clear decrease in the populations of these birds of up to 14%, which represents a total loss of 55,000 adult specimens in Europe.
Eagles and red kites, among other birds of prey, feed on animals killed or injured by the poisonous lead fragments that become embedded in their bodies when they receive the impact of a firearm. fire. By eating the meat of these animals, the birds can be poisoned and die a slow and painful death. In smaller doses, intoxication alters their behavior and physiology.
After analyzing data collected over decades by researchers across Europe, a team of scientists from the University of Cambridge in the UK have for the first time calculated the impact of lead poisoning on populations European raptors. To do this, they based themselves on the levels of this metal in the liver of more than 3,000 raptors of 22 species found dead in more than ten European countries, including Spain.
The results, published in the journal Total Environmental Sciencereveal that, for ten species of raptors, poisoning by this ammunition alone caused the disappearance of some 55,000 adult birds in the skies of Europe.
“The most affected species are large raptors, such as eagles, which are naturally long-lived, raise few specimens per year and reproduce later. Examples of these species in Spain are the golden eagle and the griffon vulture,” says Debbie Pain, a researcher in the department of zoology at the British university and co-author of the book.
According to the study, even populations of species such as the common buzzard and red kite would be significantly higher without the lead ammunition, the authors calculated in collaboration with the Leibniz Institute for Zoological and Wildlife Research (Leibniz-IZW ).
A ranking of population losses
The results reveal that the total European population is, on average, 6% lower than it should be due to lead ammunition poisoning. Thus, the work suggests that the European population of white-tailed eagles (Haliaeetus albicilla) is 14.4% lower than it would have been had it not been exposed for more than a century to lethal levels of lead in some of its foods.
Followed closely by the golden eagle (Aquila chrysaetos) and the griffon vulture (fulvus gypsum), whose populations are respectively 13.2% and 12.1% smaller than they would have been under other circumstances.
Goshawk populations (Accipiter gentilis) are 6% smaller, those of the bearded vulture (Gypaetus barbatus) 4% and red kites (milvus milvus) and Marsh Harrier (aeruginous circus), 3%.
Common Buzzard populations (buteo buteo) are 1.5% smaller, but that equates to nearly 22,000 fewer adults of this widespread species, researchers say.
Alternatives to lead in hunting
According to scientists, there are solutions to avoid this poisoning: hunters have several alternatives to lead cartridges for shotguns and rifles. “Lead poisoning of birds of prey can be eliminated by replacing non-toxic lead ammunition“, emphasizes Pain.
In this regard, efforts to promote a voluntary ban on lead shot in the UK, for example, have had no effect. In a study published last month, the authors showed that more than 99% of pheasants shot in the country are still shot with lead, despite hunting groups urging their members to switch to non-toxic lead from 2020. goal to phase out the use of lead by 2025.
Currently, only two European countries – Denmark and the Netherlands – have banned lead shot. The first plans to maintain the ban on lead bullets for rifles.
“The European Union and the United Kingdom are both considering a legal ban on all lead ammunition due to the effects on wildlife and the health of human consumers of wild game meat, but many hunting groups oppose it. .adds the researcher.
The work shows that the decline in raptor populations requires “strong action, included in legislation, whether for habitat destruction or deliberate poisoningconcludes Rhys Green, conservation scientist at the University of Cambridge and lead author of the study.
Rhys Green et al. “The impact of lead poisoning from ammunition sources on raptor populations in Europe” Total Environmental Science