Mercury and the Wood Thrush

Biologists in New York state are netting wood thrushes in the Catskill Mountains and testing them for mercury levels. The study is meant to assess the future health of the New York City water supply. Mercury is already present to some degree within the reservoirs due to pollution drifting from coal-fired power plants in the midwest. (Thus the state warns against fish consumption from lakes and streams even in the Catskills.) There is danger that levels of mercury and other contaminants could increase if birds like the wood thrush decrease due to mercury poison. Thrushes are one of many species that keep the insect population under control; barring that control, the ability of forests to filter pollutants out of the watershed could be greatly reduced.