Heavy Metal Songbirds

As if songbirds didn’t have enough to contend with! Not only is their Latin American winter habitat threatened as forest canopy coffee growing gives way to full-sun plantations (see "Grounds for Change," cover story, November/ December 2005), but a recent survey of the birds in New York State finds they’re also dealing with high body levels of mercury.

The study was conducted by biologist David C. Evers, executive director of the Biodiversity Research Institute in Maine. The highest concentrations were found in Bicknell’s thrush, a species that’s listed as threatened in the region. A 2004 report by the group found that 17 percent of loons in New York’s Adirondack Park were "at risk" for harmful effects of mercury contamination. Governor George Pataki has recently proposed cutting mercury emissions from New York State power plants, though the changes would not go into effect until 2010.

Evers says his findings also indicate that acid rain has leached calcium (an essential ingredient in the formation of eggshells) out of the soil. "The combination of acid rain, mercury and low calcium levels makes it hard for the birds to produce eggs and fledge young," Evers says.