"There was no reason to think that mercury would be a problem there"… So it was a surprise when the researchers found mercury in the blood of every Bicknell’s Thrush they sampled on Hispaniola.
by Abby McBride
Leaves are unfurling, insects are starting to emerge, and our summer birds are flocking back to North America. But they may be carrying a toxic cargo from their tropical wintering grounds, according to an unexpected finding by researchers from the Cornell Lab, Vermont Center for Ecostudies, and Syracuse University.
In the early 2000s, a group of biologists began keeping an eye on mercury levels in the Bicknell’s Thrush, which nests in mountaintop spruce-fir forests of the Northeast. This rare thrush’s high-elevation breeding grounds are particularly exposed to airborne pollutants such as mercury, a heavy metal that industrial sources pump into the air at the rate of some 2,300 metric tons per year globally. Mercury can harm wildlife when it settles and finds its way into the food web.
Most of the Bicknell’s Thrush population winters in the tropical forests of Hispaniola, so the researchers, with funding from the John D. and Catherine T. MacArthur Foundation, decided to include this Caribbean island in their study…