• Machinist@lemmy.world
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      1 day ago

      My guess is that migratory waterfowl eat lead shot when ‘grazing’ the bottom of wetlands. This bio-concentrates the lead in eagles when they prey on ducks and such.

      • Kilgore Trout@feddit.it
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        1 day ago

        @vaultdweller013@sh.itjust.works Probably that too, but the major cause is that hunters eviscerate the prey on the spot, so that the meat will last longer and retain a better taste.
        Despite not being a biologist, it is a topic I deeply care about. I have held a few presentations too, for friends and university colleagues.

        edit: It may be relevant to share that lead bullets in wetlands are banned EU-wide (where I am based) since 2023, because of the very issue with waterfowl you mentioned.

        • Machinist@lemmy.world
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          1 day ago

          Lead shot for waterfowl hunting has been banned in the US for a few decades. It’s still used for upland bird hunting. I think it’s still frequently used illegally for waterfowl.

          Not an expert, but have a decent layman’s understanding. Could totally be wrong about the next part:

          It’s my understanding that lead contamination of wild animals through hunting primarily occurs due to various sizes of bird shot. The greater surface area allows a much higher level of contamination. It also forms lead dust in the shell from friction and when fired. It’s also easier for animals to eat it. Rifle rounds and slugs are fairly inert as the larger size prevents most consumption and less absorption when it is consumed.

          • Kilgore Trout@feddit.it
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            17 hours ago

            The greater surface area allows a much higher level of contamination

            Bird hunting is typically done with carttridges filled with tens or hundreds of pellets, to maximise the surface of the shot and enhance chances to actually hit the prey.
            Most of the pellets in this cloud do not hit anything, hence they just directly fall in the water/ground.