Dench said: “Up to 100,000 water birds in the UK are expected to die each year from lead poisoning, and that’s maybe a million across Europe.
“It’s a really big effect and enough to be pushing some species towards extinction.”
Scientists and conservation groups have long warned lead shotgun pellets can contaminate habitats and harm wildlife after being deposited in the environment.
Dench said many people were unaware of the scale of the problem.
“Every time you shoot a cartridge there can be up to 300 small pellets of lead that are spread into nature,” she said.
“Overall in the UK every year that amounts to somewhere between 7,000 and 13,000 tonnes of lead being spread into nature.
“Birds, particularly water birds, will mistake it for food or grit and eat it, and that is ground down in their stomachs. That’s how they become lead poisoned.”
