A new, large-scale, nationwide study shows high levels of lead in both bald and golden eagle populations across the country. As reported in the Washington Post, the research, jointly done by the US Geological Survey, the US Fish and Wildlife Service, the Virginia Department of Wildlife Resources, West Virginia University, and Conservation Science Global examined almost 2,000 eagles in 38 states over eight years and found that about half the raptors had elevated levels of lead in their system. Lead, a toxin, can lead to neurological and respiratory problems, weakened bones, and death.
It wasn’t that long ago that eagles were at risk of extinction because of exposure to chemicals like DDT. Since the 1970s and the Endangered Species Act, eagles have staged a remarkable comeback. Today, there are about 350,000 eagles in the continental US and they were removed from the endangered list in 2007.
This study found signs that eagles are repeatedly exposed to lead throughout their lives. Often, this toxic metal is ingested when the eagles are feeding on animals that were killed by lead shot. It doesn’t take much to sicken an eagle. Even a tiny splinter from a bullet is enough. As Alex Wehrung of the Wildlife Center of Virginia said, “A lead fragment even the size of a grain of rice is enough to kill an otherwise healthy bald eagle.”
Other sources of lead, according to the article, are “mining, power plant emissions, aviation fuel, industrial paints and improperly discarded lead acid batteries.” In addition, riverfront development is forcing eagles away from the water and from the fish that would otherwise be a mainstay in their diet. Instead, as the birds move inland, they rely more on scavenging from carcasses.
In the Washington, DC region, the study found that eagles had lead concentrations in their bodies higher than the “threshold for clinical lead poisoning.” While not enough to threaten eagles with near-term extinction, the data indicate eagle population growth has been suppressed by several thousand individuals, or almost four percent.
The federal government banned lead ammunition for waterfowl hunting in 1991. Because lead poisoning contributed to the near extinction of the condor, California banned lead ammunition for all hunting and other states have or are considering partial bans of lead shot.
The recovery of an endangered species is never a smooth and orderly process. Threats continue to arise and conservationists have to be continually alert for the next, new danger. And, if you run across an eagle or other raptor that appears to be sick or injured, don’t try to help it unless you’ve been trained. Instead, contact a local rehabilitator or raptor center.
Frank Gallagher is a landscape and nature photographer based in the Washington, DC, area who specializes in providing a wide range of photograph services to nonprofit organizations. He manages NANPA’s blog and can be found online at frankgallagherphotography.com or on Instagram @frankgallagherfoto.