Berlin (dpa) – sea eagles selectively sort out coarser ammunition remnants when eating carcasses. However, smaller – often toxic – particles are swallowed by the birds, as researchers from the berlin-based leibniz institute for zoo and wildlife research (IZW) have now shown in a study.
Bullets that only deform or break into pieces of at least nine millimeters in coarseness are therefore a suitable hunting ammunition to prevent metal poisoning. Lead-containing projectiles, on the other hand, usually break down into numerous tiny metal particles.
"The study once again proves where the problem lies," said rainer altenkamp, chairman of the nature conservation association (nabu) berlin, referring to lead-containing ammunition. It is considered the main cause of death in sea eagles (haliaeetus albicilla). "Other carrion-eating birds are also affected by this risk," explains oliver krone from the IZW. "Our observations show that apart from sea eagles, ravens and buzzards are the main consumers of carcasses."
In tests with non-toxic metal parts, the IZW researchers proved that the sea eagles tracked down coarser, hard particles primarily by feeling them with the tip of their beaks or spat the particles out again after noticing them in their beaks. The researchers published the study in the journal "european journal of wildlife research". The results were not surprising. "Nobody likes to eat coarse metal parts – not even sea eagles," said altenkamp, head of the working group for the protection of birds of prey at nabu.
During examinations of sea eagles in the small animal clinic of the free university of berlin, almost only small lead fragments have been found in the stomachs of the birds, altenkamp reports. About 10 to 15 poisoned sea eagles were treated in the clinic each year. Most of them did not survive. Lead impedes the formation of blood and the transport of oxygen. "The sea eagles suffocate over a period of several days and suffer horribly," the expert said.
Lead ammunition is banned in the state forests of many federal states. But not beyond that. Altenkamp criticized that it was no longer possible to explain on rational grounds why it was still allowed to be fired in germany. According to information, there are currently around 500 pairs of sea eagles living in this country. The population has developed well since the end of the 1990s. Before that, the now-banned pesticide DDT had decimated the population.