JACKSON, Wyo. — Research suggests the golden eagle population in Yellowstone National Park (YNP) is facing threats from toxic levels of lead in scavenged carrion hunted outside the park.
Teton Raptor Center says Wyoming is home to the “core population” of golden eagles in the U.S. According to Douglas Smith, former wildlife biologist for YNP and editor of the new book Yellowstone’s Birds, Wyoming has ideal golden eagle habitat and might have more golden eagles than any other western state. Smith says these birds are the most capable predator that he’s ever studied.
“You might be able to call golden eagles a keystone predator for aerial ecosystems.”
Douglas Smith
“You might be able to call golden eagles a keystone predator for aerial ecosystems,” Smith tells Buckrail. “I would argue they’re the keystone predator of the avian world. If you take them out, it’s going to throw a lot of things off.”
While bald eagles primarily eat fish, carrion and waterfowl, Smith says he doesn’t think there’s anything that a golden eagle can’t kill. They hunt everything from a rabbit or a yellow-bellied marmot to bigger animals like pronghorn fawns, and have even been seen bringing a coyote pup up to a nest.
Smith says golden eagles also scavenge carcasses, and an ongoing study is investigating how the wolf, cougar and grizzly bear population recoveries have caused a decrease in elk numbers and consequently fewer winter elk carcasses available to be scavenged.
Another component of the research has also included radio-marking a golden eagle for the first time in Yellowstone’s history. Smith says the results highlight how lead poisoning is a transboundary threat to birds in the Greater Yellowstone Ecosystem (GYE).
Smith tells Buckrail the radio-marked bird “flew north of the park during the hunting season, scavenged carrion that had been shot with lead bullets and died from lead poisoning. This is a very important issue, picking up lead from hunter-killed game.”
The golden eagle was found and sent to a lab, where toxic levels of lead in its blood were confirmed.
According to the American Bird Conservancy, an estimated 16 million birds are poisoned by lead every year. Recent data from the National Institute of Health shows the number of species affected and geographical spread of lead-poisoning cases is increasing. The data also reveals that lead at non-lethal levels has been found to compromise birds at lower concentrations in the blood than previously thought.
Additional research published in February 2022 in the journal Science found that almost half of all bald and golden eagles sampled had chronic, toxic levels of lead high enough to suppress population growth.
Last month, Dr. Rebecca Vincent-Sturdivant with Animal Medical Center of Wyoming told News 8 that about a dozen wild birds have been treated for lead poisoning in the past couple of months, primarily coming from ammunition and fishing line sinkers. But Wyoming Senators John Barrasso and Cynthia Lummis cosponsored legislation earlier this year to prohibit the U.S. Fish and Wildlife Service, U.S. Forest Service and the Bureau of Land Management from banning the use of traditional lead ammunition or tackle on public lands.
Grand Teton National Park prohibits the use of lead ammunition for elk reduction hunting, and the use of non-lead rifle ammunition is encouraged when hunting elk and bison on the National Elk Refuge. Teton Raptor Center, based in Jackson, encourages the use of lead-free ammunition and tackle through Sporting Lead-Free, “a non-political initiative to voluntarily reduce lead consumed by wildlife and people.”
