bald eagle, whose revival Considered one of the greatest conservation successes of the 21st century, it faces a major threat: lead poisoning.
Researchers who studied the feathers, bones, livers and blood of 1,200 bald eagles and golden eagles, another bird of prey in the Northern Hemisphere, found that nearly half of them had been repeatedly exposed to lead, which could lead to death and slow population growth. .
Scientists believe that the main source of lead comes from the spent ammunition of hunters who shoot the animals, which the eagles then harvest, usually in winter. which was published on Thursday in the journal Science.
Almost a third of the birds tested also showed signs of acute poisoning or short-term exposure to lead. according to researchled by scientists from the US Geological Survey, Conservation Science Global, Inc. and the US Fish and Wildlife Service.
The effects of lead poisoning are devastating, said Vincent A. Slabe, the study’s lead author and wildlife research biologist at Conservation Science Global in Montana.
According to him, lead poisoning can prevent the eagle from properly digesting food, eventually leading to starvation. According to him, this can lead to such a serious loss of mobility that the eagle will lose the ability not only to fly, but to move at all.
“Lead can affect every system in an eagle’s body – their respiratory system, their digestive system, their reproductive system,” Dr. Slabe said.
The study, which examined bald eagles and golden eagles from 38 states, is the first to look at the impact of lead poisoning on bird populations on such a large scale, said Todd E. Katzner, a wildlife research biologist with the USGS. .
The study also found that the poisoning slowed the population growth rate of bald eagles by about 4 percent and golden eagles, which number about 35,000, by 1 percent. According to researchers, the population of bald eagles currently exceeds 300,000 individuals.
“These percentages seem small, but over time, thousands and thousands of individuals disappear from the population” due to lead poisoning, Dr. Katzner said.
Bald eagles were extirpated a few decades ago mainly due to widespread use Synthetic insecticide DDT. A ban on DDT in 1972 and conservation efforts helped the population recover, and the bald eagle disappeared. excluded from protection under the Endangered Species Act in 2007.
Dr. Slabe said he hopes the report’s findings will help educate hunters and encourage more hunters to switch to lead-free ammunition.
“This is 100 percent human-caused and completely preventable,” said Laura Hale, president of the Badger Run Wildlife Rehabilitation Center in Klamath Falls, Oregon, whose organization has hosted bald eagles, golden eagles and various species of hawks. poisoned lead.
In 2018, the group tried to save an eagle that a hunter had found in the forest, unable to fly and suffocating. When Ms. Hale told the hunter that the eagle most likely got sick from feeding on piles of infected intestines – the remains left after the hunter removed the meat from the animal carcass – she said that he was amazed.
“He was terrified,” Miss Hale recalled. “He wanted to stop hunting.”
Miss Hale said she told him he didn’t have to stop hunting; he only needed to stop using lead ammunition.
Many hunters, concerned about the consequences not only for wild animals, but also for game meat consumed by people, move away from lead ammunition and started using copper bullets.
Sporting Lead-Free, a Wyoming hunting and fishing group that seeks to raise awareness of the adverse effects of lead ammunition. posted a short film with reviews from hunters who stopped using it.
“Hunters are conservationists,” said Brian Bedrosian, co-founder of Sporting Lead-Free and a raptor biologist. “It shouldn’t be a polarizing issue.”
According to him, some hunters are hesitant to change ammunition because of tradition, the misconception that copper bullets are less effective, or because they have a supply of lead bullets.
“Besides, there are still people who just don’t know,” said Mr. Bedrosyan, who says he uses lead bullets at a shooting range where he knows the ammunition won’t come into contact with wildlife.
Hannah Leonard, the group’s outreach coordinator, said she hunted with lead bullets until she came across an emaciated golden eagle waddling on the ground four years ago while hunting in Anaconda, Montana.
“Her claws were really clenched and her wings were down,” Ms Leonard said. You could tell she was in danger.
The eagle later died and Ms Leonard said the animal rescue team she called in to try and save the bird told her lead poisoning was the cause of death.
“It was not difficult for me to change the type of ammunition,” she said.
In January 2017, the U.S. Fish and Wildlife Service released a policy to phase out the use of lead ammunition and fishing tackle used in national wildlife sanctuaries, one of the latest moves by the Obama administration. Trump administration reversed the decision in less than two months.
On Friday, the service declined to say if the policy would be reinstated as a result of a new study.
The country has a ban on the use of lead shot for waterfowl hunting since 1991, according to the service.
California bans lead munitions statewide, including on federal lands, primarily to prevent adverse effects of lead on the endangered California condor.
“The U.S. Fish and Wildlife Service uses the best available science to conserve wildlife populations and evaluate compatible uses for the land we manage, and in accordance with applicable local, state, and federal laws,” a spokeswoman for the agency said. Vanessa Kaufman. said Friday.
Dr. Slabe said that hunters, once educated, would voluntarily stop using lead ammunition.
“Hunters are very receptive to this issue,” he said. “Hunters are the solution to this problem.”