Story at a glance
- A new study says bald eagles are being threatened by spent lead ammunition left in the carcasses they feed on.
- The study found poisoning from eating contaminated carcasses has reduced their population growth by 4 to 6 percent annually in the Northeast.
- Researchers said it has the potential to erase the progress the species has made over decades.
As the number of American bald eagles has continued to soar in recent years, researchers are now warning the species’ reemergence is being threatened by lead poisoning from gun ammunition.
Bald eagles once teetered on the edge of extinction, reaching an all-time low of 417 known nesting pairs in the continental U.S. in the early 1960s.
Decades of federal protections and the banning of the harmful pesticide DDT in 1972, however, fueled the eagle’s comeback over several decades, and in March of 2021, the U.S. Fish and Wildlife Service announced an estimated 316,700 bald eagles were thriving across the country.
Bald eagles continue to be protected despite being taken off the endangered species list in 2007, as anyone who kills the iconic bird could face a felony charge that comes with two years in prison and a fine of up to $250,000.
But a new study published in the Journal of Wildlife Management argues those gains are being threatened by spent lead ammunition left in the carcasses of animals the eagles feed on.
The study found poisoning from eating contaminated carcasses has reduced their population growth by 4 to 6 percent annually in the Northeast, a rate that has the potential to erase the progress made over decades.
“Hopefully, this report will add information that compels hunters, as conservationists, to think about their ammunition choices,” Krysten Schuler, a researcher from Cornell University and senior author of the study, said in a statement.
“Even though the population seems like it’s recovered, some perturbation could come along that could cause eagles to decline again,” Schuler added.
Eagles often scavenge carcasses of deer, pheasants and other wildlife that may harbor lead or lead fragments.
When the birds ingest it in large quantities, the lead has harmful effects on the animal’s nervous and reproductive systems. Poisoned eagles may experience loss of balance, tremors and impaired ability to fly, and eventually lead to death.
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