CHARLOTTE, NC (Bruce Henderson/The Charlotte Observer) - A bald eagle the Carolina Raptor Center released at Lake Wylie on Tuesday was a lucky survivor. The toxic levels of lead that coursed through her bloodstream didn't kill the bird, which was found injured south of Charlotte in Chester County, South Carolina.
Other eagles haven't been so fortunate, with some dying from lead poisoning. The State reported earlier this month that more than three-quarters of the eagles tested at a rehabilitation center in South Carolina's Lowcountry last year had potentially harmful levels of lead in their blood.
Toxic levels have also been reported in eagles in other states, and evidence suggests that eagles are being exposed after eating the remains of animals killed by hunters who use lead ammunition.
Dave Scott, the Carolina Raptor Center's staff veterinarian, considers the link between lead poisoning and gun ammunition to be solid. And it doesn't solely affect eagles.
All five of the lead cases the center saw last year were in vultures, birds that make their living eating dead animals. Bald eagles get about half their diet that way, Scott said. The center has also detected lead in red-tailed hawks, red-shouldered hawks and barred owls -- animals that will eat carcasses that are readily available.
"The more we look, the more we see it," Scott said.
Lead shot is so prevalent that the center now X-rays the road-killed squirrels that volunteers collect to feed the birds of prey. About a third of the squirrels they examine have lead in them.
Bald eagles are considered a conservation success story, but they also show the danger of toxic substances in the environment.
Eagles live near bodies of water such as lakes and rivers, and feed mostly on fish. But for all their size -- their wings can span nearly eight feet -- bald eagles numbered only a few hundred nationwide by the early 1960s. Federal officials alarmed at the potential extinction of the national symbol in 1972 banned the pesticide DDT, which made egg shells thin and easy to break.
By 2007, with bald eagles rebounding to nearly 10,000 nesting pairs, they were removed from the endangered-species list.
The eagle that came to the Carolina Raptor Center on Feb. 5 arrived with a bloody cut on the top of its head and puncture wounds on the left side of its body, all apparently from a fight with another eagle. It also had high lead levels in its blood -- five times the level considered toxic -- and tightly clenched toes on one foot, a possible sign of lead poisoning.
Otherwise, the eagle, believed to be a female because of her large size, showed no symptoms of lead toxicity such as loss of balance or reduced ability to fly, Scott said. The center's staff healed its lacerations and administered a drug that is used to treat lead poisoning.