Authorities monitoring incidents affecting eagle populations in the United States have uncovered persistent dangers that could cause declines in eagle numbers.
Todd Katzner, a wildlife biologist with the Boise, Idaho-based U.S. Geological Survey (USGS), told Fox News Digital in an email that lead exposure in birds of prey, including eagles and vultures, is a global phenomenon.
He said the phenomenon can be seen on every continent, as humans hunt animals and leave bullets behind, and because birds that eat dead animals leave ammunition remnants embedded in their carcasses.
In a paper recently published on Science.org by the USGS and collaborators, researchers found that among 448 birds collected across the United States, 50 percent of the winged animals had evidence of chronic lead poisoning.
“In this case, ‘chronic’ means ‘repeated exposure,’ meaning 50 percent of the eagles had been repeatedly exposed to lead,” Katzner said.
“Most of the other subjects also had evidence of lead exposure, but not as frequently as the 50 percent who showed chronic exposure,” he said.
In February 2023, authorities in Lancaster County, Pennsylvania, experienced an incident in which a bald eagle, an American bird, died from lead poisoning.
“The eagle is supposed to be a powerful symbol of America, and here it lies lifeless. [he] “Hunting has lost the war on lead poisoning,” officials at Raven Ridge Wildlife Center in Washingtonboro, Pennsylvania, wrote in a Facebook post in 2023, urging hunting enthusiasts to “switch to lead-free.”
Three months ago, another eagle was found dead from lead poisoning in Lancaster County.
In January of this year, a bald eagle suffering from lead poisoning was found in Potato Creek State Park in Indiana and transported to the Humane Indiana Wildlife Rehabilitation and Education Center.
“Our team began stabilization care, hydration, critical care diet replacement, and chelation therapy. The lead levels were high. [a] “He was in poor health so we weren’t too surprised that he sadly passed away overnight,” Humane Indiana Wildlife officials wrote on Facebook.
“Lead fragments the size of a grain of rice are lethal to a mature bald eagle, and a standard 150-grain lead bullet can poison and kill 10 bald eagles,” the post continued.
“The deadly metals accumulate in the eagle’s body, [its] “Lead is a deadly substance and there is no safe amount of lead exposure, which is why it is often referred to as the ‘silent killer,'” the post also noted.
“Hunting provides an important food source for these birds, but it can also be a source of lead,” Katzner said.
He said avian scavengers can become poisoned by lead by finding prey shot by hunters or the remains of the prey.
“When a lead bullet hits an animal, it breaks into dozens, hundreds, or even thousands of pieces. [target]They often leave behind debris that contains lead fragments,” Katzner said.
“If a hunter is unable to catch their prey, lead fragments will be left behind in the animal’s carcass.”
He added that birds often eat these carcasses and debris and are highly susceptible to lead poisoning.
About 70 to 90 percent of an eagle’s diet is fish, and according to the American Bald Eagle Foundation, eagles “will eat what is most available and requires the least energy to acquire.”
Katzner said there is solid evidence that using lead-free ammunition helps reduce the incidence of lead poisoning.
In addition to ingesting lead ammunition, lead poisoning can also occur through diet.
“Other birds, such as red-legged hawks, that eat earthworms can also have high rates of lead poisoning. [the] “You have lead in your body,” Katzner said.
