With hunting season well underway, officials at The Wildlife Center of Virginia are urging hunters to take steps to curb lead poisoning of Virginia wildlife. The Center’s effort comes just days after the death of a Bald Eagle – an adult female – admitted to the Center with high lead levels.
Each year the Center treats about 2,500 wildlife patients from all across Virginia, including Bald Eagles, and an alarming number of eagles admitted for care display signs of lead poisoning. Thus far in 2011, for example, the Center has admitted 29 Bald Eagles – three of these showed signs of lead toxicity, and another 14 had measurable levels of lead. As little as 1 part per million of lead in an eagle’s blood is usually lethal. In spite of intensive treatments to purge lead from the systems of the poisoned eagles, many die from this lethal contaminant.
Routine radiographs show that many of these eagles are exposed to the highly toxic metal by ingesting lead shotgun pellets or bullet fragments. The eagles ingest these fragments while scavenging animals that have been shot but not recovered by hunters, or by feeding on the entrails of game animals, like deer, which have been harvested and “field dressed.”
Field dressing is the practice of removing the internal organs from animals harvested for human consumption, in order to preserve the quality of the meat. Typically, these entrails are simply left on the ground. Even the smallest bit of lead from bullets or shot left in these internal organs can quickly disable or kill a bird like a Bald Eagle when it feeds on these remains. For this reason, the Wildlife Center is urging hunters to either switch to bullets and shot which do not contain lead, or to bury or cover the animals or animal parts left in the field.
According to Dr. Dave McRuer, Director of Veterinary Services at the Wildlife Center, the eagle that died this week came from Caroline County. It had been seen on the ground, unable to fly. The bird was eventually captured and brought to the Wildlife Center on Sunday, November 13. Upon admission, the bird displayed the classic indications of lead toxicity – the bird was lethargic, unable to stand, experiencing tremors, and had poor muscle control. Blood tests conducted at the Center indicated levels of lead in the bird’s blood that were “off the charts” – beyond what can be tested on the Center’s lab equipment. While chelation therapy was started immediately, the bird died on Monday, November 14. “This appears to have been a classic case of poisoning as a result of the ingestion of lead shot,” McRuer concluded.
The eagle was wearing a metal leg band which had been placed on the bird in 2006, in Cecil County, Maryland. Banding records maintained at the federal government’s National Bird Banding Laboratory indicated that the female eagle hatched in 2004. “At seven and a half years of age,” McRuer noted, “this adult eagle was in the prime of her breeding life. Unfortunately, as a result of this preventable death, she will never again have the chance to contribute to the recovery of her species.” McRuer went on to explain that the bird appeared to have been in perfect condition, other than the lead poisoning.
According to Ed Clark, president of the Wildlife Center, for decades the ingestion of lead shot resulted in deaths of staggering numbers of ducks, geese and swans. “Prior to a nationwide ban on the use of lead shot for waterfowl hunting, an estimated four million ducks and geese died annually as a result of swallowing lead pellets that had been fired over wetland areas by waterfowl hunters. The birds would find the pellets as they sifted through bottom sediments looking for food. A single pellet that lodges in the digestive tract of a bird can be fatal,” Clark stated.
In an effort to curb these losses, a prohibition on the use of lead shot for waterfowl hunting was imposed in 1991 by the federal government. The use of steel and other lead-free materials for the manufacture of shot has dramatically reduced the amount of lead in wetland habitats.
Clark drew a sharp contrast between the waterfowl deaths and those of the eagles. “The eagles are not randomly picking up loose pellets from their environment, as did waterfowl. The eagles are getting the lead by eating other animals, or parts of other animals — ones that have been shot.” Often when hunters shoot upland game, such as doves, rabbits or squirrels, the downed animals are very difficult to find. State law requires hunters to make a good faith effort to recover any game animal that has been killed or wounded in the course of legal hunting. “Unfortunately, many of these animals are never found. They’re simply left where they fall, creating an attractive but deadly meal for scavengers,” Clark stated.
It is also routine for farmers and “varmint hunters” to shoot nuisance animals, such as groundhogs, and deliberately leave the dead bodies out for scavengers to eat. However, these shot-filled bodies are toxic time-bombs. The tragedy of it all is that these poisoning deaths are almost totally avoidable, Clark noted.
According to Clark – a gun collector, avid shooter, and lifelong hunter – there are now alternatives to the use of lead-based ammunition for hunting. “Several companies are now manufacturing bullets made of solid copper. They are ballistically identical to lead, and are every bit as effective.” While Clark still uses lead bullets for target shooting, he has switched entirely to copper bullets for hunting. “There is a lot of false information out there suggesting that copper bullets are not as effective as lead. The bottom line is that, if you miss your quarry, or fail to bring it down with a single shot, it is not the bullet’s fault!”
Clark points out that those hunters who refuse to give up their traditional lead projectiles can still help eliminate the risk posed by lead shot by simply burying or properly disposing of animal carcasses or entrails. Covering the remains or discarded parts of shot animals with brush or sticks could largely eliminate access to these toxic morsels by avian scavengers, particularly birds like eagles and other raptors. When eagles and other scavenging birds find and eat these carcasses, they swallow the bullets and lead pellets along with everything else. Unfortunately, even tiny particles of lead can become lodged in the digestive tract; digestive fluids leach the heavy metal into the blood stream and body tissues, affecting the nervous system and internal organs. Affected animals may appear lethargic and weak and are unable to stand or fly, even though there may be no outward signs of injury.
Even nestling eagles may face the risk of lead poisoning. In late April, three Bald Eagles were rescued from their nest at the Norfolk Botanical Garden and brought to the Wildlife Center after their mother was struck and killed by a plane at the Norfolk airport. One of those six-week old eaglets tested positive for exposure to lead – likely from ingesting some food that contained a lead fragment brought to the nest by a parent.
Anyone finding an injured eagle or other wild animal is urged to contact a Conservation Police Officer or the Wildlife Center immediately. Often, an animal’s chance of survival depends upon the speed with which it is presented for treatment. This is especially true in poisoning cases.
“Losing a Bald Eagle is a really sad event,” said Clark, “especially when the cause of the bird’s death is so preventable. We can only hope that the tragic loss of these eagles will remind everyone that bullets and shotgun pellets can kill twice.
“If you hunt, make every effort to recover your prey. If you are shooting nuisance animals, dispose of them properly. If you are field dressing game, be sure to take an extra few minutes to bury or cover the discarded entrails. The death of even a single Bald Eagle is just too high a price for human negligence or laziness,” Clark concluded.
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