Preparing for firearm hunting season for white-tailed deer, Brian Bird visited a shooting range recently to sight in his rifle – recommended after an off-season, and necessary since he’s switching bullets, to a type he’s using for the first time in his several decades of hunting.
In a shack atop a meadow sloping through woods in Whitehall on the southeastern edge of the Adirondacks, Bird steadied his Remington Model 700 bolt action rifle on a rest and aligned the borehole with a square paper target 50 yards away.
Loading his bullet, he peered down his scope and pulled the trigger, then shifted his aim to 100 yards for three more shots, adjusting the scope’s angle slightly each time until satisfied with his accuracy.
“I’m pleasantly surprised,” said Bird, who chairs the New York chapter of Backcountry Hunters and Anglers, which advocates for hunting, fishing and conservation on public lands.
This season, Bird will hunt with non-lead ammunition made entirely of copper. It’s a choice the New York State Department of Environmental Conservation (DEC) and Department of Health are encouraging the state’s more than 550,000 licensed big-game hunters to make for the benefit of both wildlife and human health, assisted by Cornell experts who have researched how lead ammunition impacts eagle populations and how best to communicate its risks.
Lead is a neurotoxin for which there is no safe level, especially for children and pregnant women, according to the Centers for Disease Control and Prevention. Despite successful efforts to remove it from gasoline, paint, household products and drinking water, lead persists in ammunition used by 95% of hunters pursuing white-tailed deer.
Lead rifle bullets shatter on impact into hundreds of fragments, killing an animal quickly and humanely. But the fragments – sometimes too small to see – can spread as far as one foot from the wound channel. That can potentially pepper game meat and carcasses with toxic particles, creating a hazard for humans and wild scavengers, including bald eagles. Consuming a lead fragment as small as a grain of rice can be lethal to an eagle.
State agencies are stepping up education and outreach to promote voluntary adoption of non-lead alternatives, acting on recommendations from their Lead Ammunition Working Group, a multidisciplinary partnership that includes the Cornell Wildlife Health Lab. So far, the DEC has integrated the issue into an online hunter education course, shared a Cornell-produced educational video and introduced a pilot rebate program, whose effectiveness Cornell researchers will study.
Conservation-minded hunters like Bird and other advocates are now working to raise awareness and ease concerns, recommending lead-free ammunition as an equal and safer alternative.
“The problem and solution seem surprisingly simple at first,” said Dominic Balog-Way, research associate in the Department of Communication in the College of Agriculture and Life Sciences (CALS). “After all, why would anyone knowingly eat lead, or fire lead ammunition that may be consumed by vulnerable wildlife, when there are alternatives? Our in-depth research, however, shows the issue is much more complicated.”
In mid-September, a resident reported a downed bald eagle – lethargic and unable to lift its head – behind a home in Elba, north of Batavia in Genesee County. A DEC environmental conservation officer transported the bird to a wildlife rehabilitator near Rochester, who covered its head to reduce stress, cleaned it of black flies and administered fluids. The next day, the rehabilitator drove the eagle two hours to the Janet L. Swanson Wildlife Hospital in Ithaca, part of the College of Veterinary Medicine (CVM).
Despite aggressive care, the eagle died the following day. It would become one of nearly 900 bald eagles necropsied by the New York State Wildlife Health Program, a 13-year-old partnership between the Cornell Wildlife Health Lab, housed in CVM’s Animal Health Diagnostic Center, and the DEC’s Wildlife Health Unit.
Lead from ammunition enters the food chain, exposing humans and animals to health risks from the toxic lead particles.
After testing negative for bird flu, the deceased bald eagle’s thin frame, pale heart and distended gallbladder suggested lead poisoning to a Cornell pathologist. Toxicology tests of liver tissues soon confirmed a severe case – with lead levels more than seven times above a toxic concentration.
Such diagnoses are not uncommon.
In New York, as across the lower 48 states, bald eagles – iconic symbols of the nation, delisted as an endangered species in 2007 – are a conservation success story. Between 1990 and 2018, the number of breeding pairs increased 28-fold, from just 13 to 369, according to the DEC.
But Cornell researchers, partnering with state wildlife agencies including the DEC, have found that lead toxicity caused a drag on that growth, akin to driving with a foot on the brake, said Krysten Schuler, a wildlife disease ecologist who directs the Cornell Wildlife Health Lab.
Among more than 1,200 bald eagles examined over nearly 30 years in seven northeastern states, including New York, researchers found that 78% were exposed to lead and 37% had toxic levels. Comparing actual eagle populations with what they could have been absent lead exposure or poisoning, they found lead had slowed the growth rate by about 5%. A New York-specific study reached a similar conclusion.
While 5% might not sound like a huge amount, Schuler and Kevin Hynes, a biologist who leads the DEC’s Wildlife Health Program, said the studies confirmed lead poisoning has a population-level impact. That diminishes eagles’ ability to manage additional challenges, including the deadly bird flu that emerged in 2021.
“They’re right at the edge of how many insults they can absorb,” Schuler said. “If other things come along, like introduced diseases or wind energy development, those might be enough to change the population’s trajectory.”
