A new study conducted by the Biodiversity Research Institute in partnership with The Nature Conservancy shows unhealthy levels of mercury in songbirds and bats throughout the American northeast from Maine to Virginia.  The study— entitled: Hidden Risk: Mercury in Terrestrial Systems of the Northeast—confirms mercury contamination extends to many forms of wildlife in addition to fish.  The results show that both bats and some bird species suffer many of the same type of neurological disorders from mercury exposure as humans, especially children.  Last December, the U.S. EPA released mercury and air toxins standards for power plants to limit mercury and other toxic pollution from power plants.

Dr. David C. Evers, Ph.D., a biologist and director of the Biodiversity Research Institute, said in a Nature Conservancy news release, “While the risk of mercury to people is well known—there are more than 3,700 fish consumptions advisories issued in the U.S.—we are still learning about mercury’s effects on wildlife.  Mercury accumulation has many implications for the health and survival of wildlife species across habitats, not just those that live and feed in aquatic habitats.  Our research has found that mercury concentrations in animals that live in terrestrial environments are significant enough to cause physiological and reproductive harm.  This knowledge is creating a major paradigm shift in eco-toxicological research, assessment, monitoring, management, and policy.”

Mercury is released into the atmosphere by coal-burning power plants.  It can drift for miles before falling back to earth, often during rain and snowstorms.  Methyl mercury, the most toxic form of the pollutant, is absorbed by tree leaves that fall to the ground and then enters the food chain via small insects, worms, and snails that feed on the forest floor.  Those organisms are eaten by birds and other animals and thus enter the food chain.  Methyl mercury is now found in rivers, lakes, forests, mountains, and lowlands worldwide.

The Hidden Risk study shows that current mercury loads can reduce reproductive success in several songbird species in the northeastern U.S., including the saltmarsh sparrow and rusty blackbird, and also that bats can also build up dangerous levels of mercury in their bodies.  Birds in contaminated sites were found to be three time more likely to abandon their nests or exhibit abnormal feeding behavior, and some chicks begged less aggressively to be fed. 

Evers has been studying the effects of mercury on wildlife for 11 years.  Initially mercury impacts were studied on the common loon, and Evers found that loons with high mercury levels spend only 85 percent of their time incubating their eggs, when they need to spend 98 percent of their time on a nest to have eggs that hatch successfully.  While the research focused on the northeastern U.S. Evers said that mercury pollution is happening all over the world.  Joanna Burger, a behavioral ecologist at Rutgers University, has been studying mercury contamination in terns, skimmers, and other shore birds and says that those species are showing us how dangerous pollutants can be for people as well.  Both Evers and Burger are supporting multinational efforts to establish a global mercury treaty.