The mighty bald eagle is facing some tough times. In recent years, the population of our national bird has decreased by almost 4%, and lead poisoning is usually the reason.
A new nationwide study has found that up to 33% of examined dead bald eagles contained serious levels of lead poisoning. This clinical poisoning is mainly transmitted from an eagle’s prey such as fish or small animals. After consuming such prey, the eagles’ stomach acids break down neurotoxin and release lead into the bird’s bloodstream. The lead then travels to soft tissues around the body and eventually accumulates within the bird’s bones leading to the death of these beautiful animals.
In colder seasons eagles tend to go from natural hunters to scavengers. Scientists have found that eagles are more likely to get poisoned during the colder months when they depend more on the tainted remains of dead prey.
Bald eagles aren’t the only eagle species that are affected by this type of poisoning. Another species affected is the golden eagle. The population of these eagles is also going down. Scientists estimate only about 36,000 golden eagles survive in the lower 48 states and they, too, are often found to have lead poisoning. In a post-mortem study of 448 bald and golden eagles, about 50% tested positive for lead poisoning.
Bald eagles were on the endangered species list until 2007. They have since been removed from that list. But the lead poisoning levels reflected in this new study make researchers worry about the future of these iconic birds. Some experts wonder, are eagles really on their way back?
[Sources: The Wall Street Journal; Journal of Science; Wisconsin DNR]