Most U.S. eagles suffer from lead poisoning, study suggests
Articles and Media Coverage From Animal Defenders of Westchester (ADOW)

We advocate on all animal protection and exploitation issues, including experimentation, factory farming, rodeos, breeders and traveling animal acts.

Most U.S. eagles suffer from lead poisoning, study suggests

February 17, 2021

Most bald and golden eagles in the United States have been repeatedly exposed to lead throughout their lives, new research shows. The primary source of exposure is ammunition—as eagles scavenge on the carcasses of animals shot by hunters, they can ingest lead fragments from rifle rounds and shotgun pellets.

In the study, published February 17 in the journal Science, researchers examined lead levels in 1,210 eagles across 38 states—the biggest effort of its kind to date in North America. They found that more than half of the adult birds had bone lead concentrations above 10 parts per million, which pathologists define as chronic lead poisoning.

This level of lead poisoning is slowing the population growth rate of both species, says study co-author Vincent Slabe, a wildlife biologist at Conservation Science Global, a research organization based in Bozeman, Montana. Since both species are of conservation concern, anything that might suppress their numbers is therefore highly relevant, he says.

While acute poisoning can kill eagles in horrific fashion—for example causing them to become immobile and slowly starve to death—chronic exposure can also have other less visible effects, such as impairing movements and flight, reducing sperm quality, making it impossible to swallow and digest food, and lowering immunity.

The data were relatively consistent across species and regions, though some measures of lead exposure were slightly higher in the Central Flyway of the United States.

“Nearly every single eagle we tested had some lead exposure over the course of its life,” says co-author Todd Katzner, a wildlife biologist with the U.S. Geological Survey based in Boise, Idaho.

When hunters shoot creatures such as deer with lead shotgun pellets or rifle rounds, ammunition fragments can spread throughout the animal. After a kill, hunters often first gut the animal, leaving its innards on the landscape, which may be tainted by splintered bits of lead ammo. Sometimes animals that get shot escape and die later. Either way, eagles can be exposed when scavenging on tainted gut piles or carcasses.

Conservationists have long called for incentives or laws to get hunters to switch to steel or copper ammunition, which costs the same as a high-quality lead shot.

“It is really frustrating that lead poisoning in birds of prey has been well known for more than 50 years, and there have been very limited movements in the regulations adopted in most of the countries” to reduce use of lead ammunition, says Rafael Mateo Soria, a researcher with Spain’s Institute for Game and Wildlife Research, who wasn’t involved in the paper. In Eurasia, golden eagles, white-tailed sea eagles, and other large raptors are similarly widely poisoned by lead from ammunition.  

Return to: Articles and Media Coverage
Read more at Stop Hunting

WESTCHESTER4GEESE is an adjunct of ANIMAL DEFENDERS OF WESTCHESTER. We advocate against all forms of animal abuse and exploitation, including hunting, experimentation, fur, circuses and rodeos -