An estimated 16 million birds die of lead poisoning each year in the United States.  The ingestion of shotgun pellets is the most common source of lead poisoning in birds, however, the consumption of other lead objects such as lead bullets and fishing sinkers are also lethal.

Lead poisoning has been reported in every major species of waterfowl in the United States, and also occurs with less frequency in upland game birds such as mourning doves, wild turkeys, pheasants, and quail. Eagles and other raptors are the most commonly affected land birds.  Eagles and raptors scavenge on carcasses shot and contaminated with lead bullet fragments.  Other birds such as Mourning Doves mistake spent shot for seed in fields and forests, while diving birds like Common Loons swallow lead fishing tackle while foraging on lake bottoms.

When lead is ingested, it is absorbed into the blood stream and transported to tissues throughout the body.  This causes a loss of appetite and lethargy, which results in muscle weakness and weight loss, followed by the inability to fly and walk, then coma, and eventually death.  Neurological signs such as blindness and head tilting may occur, or a wing droop or leg paralysis can indicate poisoning. A bird just may not ‘look’ well, sitting quietly with fluffed feathers. A bird may also exhibit noticeable weakness, depression, loss of control and coordination of body movements.

Treatment is prolonged and expensive, sometimes costing thousands of dollars, and because most lead-poisoned animals are not privately owned, the cost is usually shouldered by non-profit wildlife rehabilitation centers and charitable organizations. Lead toxicosis can be treated with lead chelating agents, such as EDTA, and supportive care, but many birds are too severely affected for treatment to be successful. Removal of lead particles in the gastrointestinal tract or tissues of wild species is necessary to prevent continued exposure to lead.

Many local and regional studies on lead toxicity in birds and wildlife have been performed, but the first study at a nationwide scale was conducted by scientists from the U.S. Geological Survey, Conservation Science Global, Inc., and U.S. Fish and Wildlife Service.  In this study, researchers evaluated lead exposure in bald and golden eagles from 2010 to 2018 using samples from 38 U.S. states. In this study, almost 50 percent of the 1210 eagles sampled showed evidence of repeated exposure to lead.  The study revealed that lead reduces the rate of population growth for both of these protected species – 3.8 percent for bald eagles, and 0.8 percent for golden eagles annually.

One simple way to reduce lead toxicity in birds and other wildlife is to use non-lead ammunition and fishing sinkers.  Lead-free (such as copper) ammunition and fishing sinkers are readily available, and many hunting and fishing groups support and encourage their use.  Some environmental groups have called for a ban on the use of lead bullets in hunting, and, in 2019, the California Legislature approved one statewide.  Lead fishing sinkers are banned in six U.S. states – New Hampshire, Maine, New York, Vermont, Massachusetts, and Washington.  And, the U.S. Fish and Wildlife Service 2022-2023 Hunting and Sport Fishing Regulations includes a ruling that various national wildlife refuges will require or have proposed non-lead ammunition and tackle by fall 2026.  Safe disposal of fishing line and tackle is also encouraged, and many areas provide fishing line recycling containers.

In conclusion, the consequences of lead poisoning in birds is significant.  Banning or reducing lead ammunition and fishing tackle would have an incredible impact on bald and golden eagle populations, as well as other birds and wildlife.

Written by Judy Cadmus