Bald eagle population growth drops 6% due to lead poisoning caused by birds eating deer killed by hunters’ ammunition, study finds
- New study finds bald eagle populations are declining due to lead poisoning
- The birds eat organs left behind by hunters that contain rifle ammunition
- Experts say other animals are feasting on the remains and being poisoned
Bald eagles may have recovered from near extinction, but the birds are now at risk from another threat: lead poisoning.
Their population growth in the northeast is declining by up to six percent as the birds eat ammunition in organs from other animals left behind after being shot by hunters.
According to a team of scientists led by Cornell University, declining population growth may erase the cushions that protect the once endangered eagles from unforeseen events.
Researchers also noted that bald eagles weren’t the only animals to feast on animal remains left behind after a murder, as owls, crows and coyotes also eat the tainted meat and contract lead poisoning.
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Bald eagle population growth in the Northeast is slowing to six percent as birds eat ammunition in organs from other animals left on the property after being shot
“We haven’t collected data on these other species in the same way we pay attention to eagles,” said Krysten Schuler, assistant research professor in the Department of Public and Ecosystem Health at Cornell University and senior author of the study.
“We’re putting eagles as a poster species for this problem, but they’re not the only ones affected.”
Bald eagles — which have been the national bird of the United States since 1782 — were declared endangered by the federal government in 1978. But after a slow recovery, they were removed from the list in 2007.
And last year it was announced that the population of the legendary predator has quadrupled in the past 12 years, according to a recent study by the US Fish and Wildlife Service, which was reviewed by Cornell University.
According to a team of scientists led by Cornell University, declining population growth may erase the cushions that protect populations from unforeseen events.
There are more than 316,000 bald eagles in the continental US, including more than 70,000 breeding pairs.
That’s more than four times the 72,434 individuals and 30,548 pairs recorded in 2009 — and more than seven times as many as in 2007.
However, experts fear that we may soon see a decline in bird populations.
“While the population appears to have recovered, there may be some disruption that could cause the eagles to dwindle again,” Schuler said.
The problem stems from killing field dressing of hunters, removing internal organs on site.
A separate 2021 study found that bald eagles are also threatened by venom used to exterminate rats.
More than 80 percent of the dead bald and golden eagles surveyed between 2014 and 2018 were found to have rodenticide in their systems.
A separate 2021 study found that bald eagles are also threatened by venom used to exterminate rats. Pictured is a bald eagle who died from consuming rat poison
The heavy-duty venom is an anticoagulant that thins the blood of mice and rats after it is eaten and eventually kills it.
It is designed to stay longer in the bodies of its victims and can enter the system of a bird that hunts the dead rodent.
Only a small percentage of the birds had succumbed to anticoagulant poisoning, but those that did showed signs of heavy internal bleeding and were unable to form scabs or clots.
Experts said the widespread presence of this toxicant in a species only recently brought back from the brink of extinction was “alarming.”