A bald eagle flies from a sandbank with its meal in its talons off Brunswick, Maine, along the New Meadows River, on August 22, 2011.
Pat Wellenbach / AP
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Pat Wellenbach / AP
A bald eagle flies from a sandbank with its meal in its talons off Brunswick, Maine, along the New Meadows River, on August 22, 2011.
Pat Wellenbach / AP
Bald eagle populations have slowly recovered from the effects of a pesticide that nearly made them extinct decades ago. But now researchers at Cornell University have discovered that lead bullets continue to hinder the resilience of these American icons.
The use of lead bullets in bald eagle habitat has reduced population growth by 4% to 6% annually in the Northeast, even if their populations fly up in the lower 48 states from 2009 to 2021, according to a study published in Wildlife Management Magazine.
Eagles eat carrion left behind by hunters, and dead animals can be poisoned by lead bullets. The study spanned decades of data, from 1990 to 2018, and included seven states: Connecticut, Massachusetts, Maine, New Hampshire, New Jersey, New York, and Vermont.
And while this study focused on bald eagles, it could have implications for the health of other animals known to be scavengers, including crows, coyotes and foxes.
“What we have is a lot of data on bald eagles,” said Dr. Krysten Schuler, wildlife ecologist and co-director of the Cornell Wildlife Health Laboratory. “They are of the kind of posterity we’re using for this problem because we don’t have the same amount of data to do this kind of analysis on other species.”
Bald eagle – praise a “American success story” by the United States Fish and Wildlife Service – was threatened by the use of DDT, an insecticide that nearly wiped out their populations. The pesticide was banned in 1972, and eagles were introduced. Listed endangered species in the Endangered Species Act of 1973. In 2007, bald eagles were removed from the list.
The lead bullet didn’t stop the eagle’s recovery, Schuler explained, but it didn’t help either.
When a hunter shoots a deer with a lead bullet, the bullet will scatter into many small pieces. Schuler told NPR that if a hunter “processed” a cub by removing its organs, the organs left behind would carry lead fragments. The eagles unknowingly ingest lead-contaminated body parts.
Lead is toxic to everyone, but the acid in the eagles’ stomach breaks down the lead, eventually pushing it through their bodies, Schuler said.
““It’s a man-made source of death,” Schuler said.
Using other ammunition, such as copper, can help keep lead out of bald eagle habitats. Burying the organs of a carcass shot with lead bullets could also keep the contaminant from affecting eagle populations, Schuler said.
“This is definitely not an anti-poaching effort,” Schuler said. “We’re really trying to emphasize the choice and the educational component.”
Discussions about the use of lead ammunition have also reached Washington.
On the last day of President Barack Obama’s administration, the outgoing director of fish and wildlife banned lead bullets from national wildlife sanctuaries. A few weeks later, President Donald Trump’s first secretary of the interior turn it upside down.
In July 2020, Representative Ted Lieu, D-Calif., introduced a bill would ban lead ammunition on U.S. Fish and Wildlife Service land. Bill died in Parliament. At the state level, a member of the Maine Legislature, Representative Amy Roeder, introduced a bill in March 2021. The bill also died.
“Lead is a deadly poison,” Lieu told Boise State Public Radio in 2020. “We shouldn’t just spread it around with ammunition and it’s also deadly to animals.”
With the publication of the study, the researchers shared it publicly software so others can use it to investigate other species.
“When we started, we didn’t know what we were going to look for,” Schuler said. “But that’s a big question, you know, for as long as I can think of in my career.”
