Assessment of methlymercury availability to bats in New York - 2006

More than half of the species of bats in the U.S. can be characterized as foraging over water for emergent insects. There have been very few investigations measuring the exposure of mercury (Hg) to bats. Because of factors that relate to the bat’s natural history and vulnerability to anthropogenic stressors, over half of the species in the United States are listed as endangered and threatened or are under consideration for listing. Bats comprise about one-quarter of the mammalian species and constitute a substantial portion of the mammalian biological diversity in the United States. We present findings from a pilot effort to evaluate Hg exposure in multiple bat species from New York State. We sampled blood and fur from 96 bats at eight sites in New York State. Samples were analyzed for total Hg (>95% Hg in fur is MeHg). We demonstrate that 16% and 5% of the bats sampled had fur Hg concentrations that exceeded the lowest observed effects levels in dosed mice (i.e., 10.8 ug/g, fw) and furbearers (i.e., 20.0 ug/g, fw), respectively. This study demonstrates the potential risk of anthropogenic releases of Hg in the airsheds and watersheds of New York State for bats and parallels risks found in diurnal invertivores – songbirds.