Shorebirds breeding in Alaska are being exposed to mercury at levels that could put their populations at risk, according to new research from The Condor: Ornithological Applications.Thanks to atmospheric circulation and other factors, the mercury that we deposit into the environment tends to accumulate in the Arctic. Mercury exposure can reduce birds' reproductive success and sometimes even be lethal. Shorebirds may be particularly vulnerable because they forage in aquatic environments where mercury is converted into methylmercury, its most dangerous form. Marie Perkins of the Biodiversity Research Institute (BRI) and her colleagues investigated the level of mercury in Alaska's shorebirds and found that some birds breeding near Barrow, at the state's northern end, have mercury concentrations upwards of two micrograms per gram of blood.