TRAVERSE CITY, MI – Of all the lead-poisoned bald eagles Skegemog Raptor Center has seen in the past year, the recent cases have been some of the worst.
There was the eagle discovered lying on its back in an intersection near Mesick; another found immobile on its belly, wings outstretched, in a field on Old Mission Peninsula; yet another brought in from the Gaylord area with head tremors and ragged breathing.
Testing showed that all of them had sky-high levels of lead in their blood. The culprit? Ingested fragments of lead ammunition.
Cases like these are common every year at wildlife rehabilitation clinics across Michigan after deer season, explains James Manley, Skegemog Raptor Center’s executive director. It’s an unintentional consequence of hunting with lead bullets, which create fragments that eagles and other wildlife can accidentally ingest when scavenging carcasses left behind.
It doesn’t take much lead to sicken or kill a bald eagle – a piece as small as a grain of rice can be deadly. Even low levels of chronic exposure can significantly impact a bird’s life, affecting its ability to successfully fly and hunt.
That’s why Manley, along with other wildlife rehabilitators and conservation groups, is now trying to raise awareness about the potential consequences of hunting with lead.
“These last three cases were very severe. It’s heartbreaking to see,” Manley says. “People don’t know that it’s a problem.”
“It’s something you’ll never forget.”
In the late 20th century, America’s national symbol became an emblem for environmental success when a then-controversial federal ban on the use of DDT – a commercial pesticide that had nearly wiped out the species – allowed eagles to make a soaring recovery and be removed from the endangered species list. There are now 300,000 bald eagles living in the wild, up from 417 nesting pairs in 1963.
But experts say lead poses an underappreciated threat to this magnificent bird.
An eight-year study published in 2022 found that nearly half of bald and golden eagles nationwide tested positive for chronic lead poisoning. In Michigan, where the bald eagle population sits between 3,500-4,000, lead poisoning is the species’ third leading cause of death; eight eagles die of accidental lead poisoning for every one eagle illegally killed, according to the Michigan Department of Natural Resources.
Research has found the main source of this environmental toxin is lead ammunition in wild game carcasses and “gut piles” – entrails left behind when hunters clean game in the field. Lead bullets shatter on impact, resulting in countless microscopic fragments that are easily swallowed by scavenging eagles when they happen upon that free meal.
Lead fishing gear is another threat, indirectly poisoning eagles and other wildlife and waterfowl, like loons, when they consume fish that have swallowed lead sinkers or other tackle.
Toxicologists will tell you there’s no such thing as a “safe” amount of lead, for humans as well as for wildlife. In eagles, low levels of lead poisoning can cause cardiac murmurs, disruption to digestion, and abnormal, confused behavior, increasing the likelihood of injury. At higher levels, lead can result in permanent neurological damage, seizures and death.
“If you’ve ever seen an eagle that has been poisoned, it’s something you’ll never forget,” says John Buchweitz, nutrition and toxicology section chief at Michigan State University Veterinary Diagnostic Laboratory. “The animal may go blind. They can develop tremors. They can lose their ability to fly. It’s a sad statement on the truly adverse effects of a chemical, like lead, on an animal.”
Wildlife rehabilitators can sometimes successfully administer chelation treatments to slowly draw the poison out of a bird. But according to the University of Minnesota’s Raptor Center, which treats more than 150 sick and injured bald eagles each year, most found with lead toxicity either die or are humanely euthanized to alleviate their suffering.
In the eight-year study, models comparing natural and lead-caused deaths found that lead levels would stunt bald eagle yearly population growth by 3.8%. Advocates say that annual reduction may not seem drastic compared to the eagles’ overall rebound, but that it will add up over the years, challenging the birds’ hard-won recovery.
“This is a national symbol for us,” Buchweitz said. “And I think we should have the utmost respect for that national symbol. It is a reflection, in a sense, of our country and what we stand for.”
Considering non-toxic alternatives
Some conservation advocates have pushed for limits on lead ammunition, pointing to the federal ban on lead shot used for waterfowl hunting after it was determined to be causing population declines. California, where lead ammunition threatened the endangered California condor, has already outlawed its use. Meanwhile, the U.S. Fish & Wildlife Service will require non-lead tackle and ammunition at Indiana’s Patoka River National Wildlife Refuge by 2026, and is considering adding other wildlife refuge sites to that list.
But some are wary of suggesting an all-out ban on lead, fearing it would be too divisive. Hunters who oppose giving up lead may do so because they’re loyal to their preferred ammunition, or because the cost of lead remains lower than non-toxic alternatives, such as copper.
There are outdoors organizations, however, that are committed to promoting non-toxic options. In 2020, the Michigan United Conservation Clubs, or MUCC, passed a resolution to support the use of non-toxic ammunition and to educate the public on alternatives, some of which they say are actually more effective than their lead counterparts.
“Our policy is educate and encourage, try and do these things voluntarily rather than just come through a mandate,” says Justin Tomei, policy assistant at MUCC. “I think when you give hunters the tools they need to arm themselves with the proper information, that they’re going to make the right choice more often than not.”
Nationwide, some hunters are voluntarily making the switch away from lead as a result of state-level efforts. The Arizona Game and Fish Department, for example, has offered free non-lead ammunition to people hunting within the California condor’s range, as well as a special prize drawing for those who remove lead-containing gut piles. The department says 88 percent of hunters in Arizona’s condor range now use non-lead ammunition or, if they do use lead, remove their gut piles from the field.
While Michigan does not have similar programs, the Michigan Department of Natural Resources has a webpage with information about alternatives, as well as recommendations that people consider using non-toxic shot and tackle.
“Alternatives that are safer for people and wildlife do exist, and it makes sense to elevate the conversation and boost public awareness,” the DNR page says.
Slow change
Not all of Skegemog Raptor Center’s bald eagle stories are as dire as those three recent cases, each of which ended with the eagle soon dying or being humanely euthanized. Coincidentally, the acutely ill eagle picked up near Gaylord was found just a few miles from where Manley had released a successfully treated lead-poisoned eagle last spring.
But of the 17 bald eagles the center’s volunteer staff tested for lead in 2022, 13 were shown to have some degree of lead poisoning, whether low level or acute, Manley says. And experience tells him he and other Michigan rehabbers will likely see another spike in severe cases this spring, when old gut piles are once again revealed by receding snow.
So Manley will keep sharing these eagles’ stories as a way to help more people know about lead’s effects on wildlife, as well as to potentially initiate change, however gradual it may be.
“We’re going to have to use every available resource to get this out,” he says. “There’s a lot of steps I think we’re going to have to go through to get enough people on our side where it’s like, OK: let’s quit putting a known toxin into the environment.”
Find Skegemog Raptor Center on Facebook at facebook.com/SkegemogRaptorCenter and online at skegemograptorcenter.org. Learn more about lead poisoning in wildlife at the DNR’s website here.
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