A biologist studying wild songbirds in New York State has found that all 178 woodland birds he tested last year had unusually high levels of mercury in their blood and feathers, a sign that the toxic chemical has spread farther in the environment than previously thought.
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The presence of mercury in lakes and streams is already well documented, and the New York Department of Health advises people to restrict the consumption of any freshwater fish caught in most of the state to no more than one meal a week.
But Dr. Evers is one of the first scientists to test for wildlife mercury contamination beyond fish. He began his work in this area in 1998 and found that common loons, which eat fish, had highly elevated levels of mercury that made them lethargic and caused their reproductive rates to drop. He then decided to study songbirds, which never eat fish. In particular, he wanted to study the wood thrush, a small bird with a distinctive song that was once common throughout the Northeast. The population of wood thrushes has declined 45 percent in recent decades.
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Dr. Evers’s work suggests that when mercury falls on land, it is absorbed by soil and by fallen leaves that are consumed by worms and insects. Songbirds then feed on the bugs, absorbing the mercury.
More:
http://www.nytimes.com/2006/07/25/nyregion/25birds.html