By Susan Milius
When birds forage at sea, they pick up mercury and pesticide residues, which end up accumulating near nesting colonies, suggests a study in Arctic Canada.
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Some 10,000 pairs of medium-size seabirds called northern fulmars (Fulmarus glacialis) nest in a widespread colony on Devon Island 640 kilometers north of the Arctic Circle. Ponds on the island closer to the colony, where more of the fulmars’ guano and debris falls, had higher concentrations of pollutants than did ponds situated farther from the colony, says Jules Blais of the University of Ottawa in Ontario. In the July 15 Science, he and his colleagues report that three of these ponds had so much mercury that they neared or passed Canada’s limit for wildlife safety.