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Listening to the Loons

A Loon

(Photo: US Fish and Wildlife Service)

The distinctive, almost-haunting call of the common loon is to New England what the howl of the wolf is to the American West: it’s the sound of wilderness. If you’re fortunate enough to be listening to a loon, you’re almost certainly surrounded by forests and lakes, and a long way from the nearest office building, shopping center, or even paved road. But that loon you hear out in the middle of nowhere offers EPA scientists important insights into industrial pollution, habitat alternation, and other environmental stresses.

Since 2000, scientists at the Environmental Protection Agency’s Atlantic Ecology Division located in Naraganesett, Rhode Island, have been studying the common loon to better understand how environmental stressors affect wildlife. One key part of that investigation looks at mercury levels in wild loon populations. Because loons are at the top of the food chain—like people—what the scientists learn advances the science of risk assessment for both wildlife and humans.

The loon’s diet is composed exclusively of fish, which even in the wilderness often contain mercury. The mercury comes from acid rain spawned by pollution from both local and mid-western coal-fired power plants, as well as from local incinerators.

EPA scientists work with their colleagues from other federal and state agencies and with interested citizens’ groups to study how environmental factors, including mercury, are affecting the loons of New Hampshire.  Organizations such as the New Hampshire Department of Environmental Services and the Loon Preservation Committee of New Hampshire have accumulated decades of information about the environment and the loons nesting on hundreds of New Hampshire lakes.

One thing those and EPA’s own studies show is that fish and loons throughout the northeast show high concentrations of mercury. These confirm recent, far-reaching investigations revealing that accumulations of mercury in the environment are a global problem. The studies also suggest that the way to lower mercury levels in loons and other creatures that survive at the top of the food chain is to reduce emissions of mercury in the air.

The overall objectives of the EPA study goes far beyond loons and mercury. In conducting their investigation, the scientists are developing new tools and approaches to better understand how multiple stressors, from toxic contamination to habitat loss, affect a diversity of wildlife species. The scientists are working hard to keep the voice of the wilderness from going silent.

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