HomeOutdoorsStudy Reveals Nearly 50% of U.S. Bald Eagles Suffer From Harmful Lead Exposure

Study Reveals Nearly 50% of U.S. Bald Eagles Suffer From Harmful Lead Exposure

by Matthew Memrick
(Photo by Joel Lerner/Xinhua via Getty) (Xinhua/Joel Lerner via Getty Images)

A new study says nearly half of all American Bald Eagles suffer from harmful lead exposure. 

First, America’s national bird suffered from pesticides like DDT, only to rebound in large numbers, and now this.

The journal Science published the results, noting harmful levels of toxic lead in the birds. They noticed high levels of lead in 46% of the bald eagles sampled in 38 states nationwide.

The New York Post reported on the study.

Study Takes Aim At Hunters and Anglers

Since there are similarities in this lead exposure in golden eagles, scientists conclude that the raptors eat prey contaminated by ammunition and fishing tackle.

During the eight-year study, the researchers looked at the blood, bones, feathers, and liver tissue of 1,210 eagles. They saw eagles with different exposure to the lead, whether chronic or acute. 

“This is the first time for any wildlife species that we’ve been able to evaluate lead exposure and population level consequences at a continental scale,” study co-author Todd Katzner said.

Katzner, a wildlife biologist at U.S. Geological Survey in Boise, Idaho, said it was “sort of stunning” to find out that nearly 50 percent of the raptors are “repeatedly exposed to lead.”

Lead Hurting Eagles In More Ways Than One

The study recounted that small doses of neurotoxin could affect an eagle’s balance and stamina. Those factors are critical in the raptor’s flying, hunting, and reproduction methods.

Higher doses can lead to seizures, breathing issues, and even death. The researchers already estimate that the bald eagle population has dropped by 4 percent, with golden eagles dropping by one percent.

Bald eagles were coming back. They got dropped from the U.S. Endangered Species List in 2007. But with the lead rates, there’s cause for concern. These raptors may not be able to handle climate change or disease as well if they’re intoxicated with lead.

Remember, samples came from dead eagles who were electrocuted, hit by cars, or other mishaps.

Past Studies Not As Revealing About Bald Eagles

There are many coincidences between the hunters and the lead in the bald eagles.

Elevated levels of lead exposure came in the fall and winter months, often the same months for hunters. Also, eagles eat carcasses or gut piles discarded by hunters with lead shots or bullet pieces in them. The study also found more bald eagle lead poisoning in the Central Flyway or central part of America.

Study co-author Vince Slabe said just one “lead fragment the size of the end of a pin is large enough to cause mortality in an eagle.”

Slabe didn’t want to bust on hunters and supported their conservation work nationwide. They pay fees and taxes to wildlife agencies, and Slade himself has hunted deer and elk in Montana.

But he’s hoping the study can result in conversations that can help the bald eagle population. He’s hoping more hunters will switch to non-lead ammo like non-toxic ammo like copper bullets. While waterfowl hunting with lead bullets became prohibited in 1991, upland bird hunting and big game hunting have no restrictions.