Mercury in Montane Songbirds

Groundbreaking research conducted over the past 5 years by more than 50 scientists, including VINS Conservation Biologists, have yielded surprising insights on the extent of mercury pollution across the northeastern U.S. and eastern Canada. From lakes to mountaintop forests, data were painstakingly collected on air, water, fish, birds, and other wildlife at thousands of locations.

The comprehensive research reveals that not only is mercury loading higher and more pervasive than previously reported by the EPA, but it has been documented in some unexpected places. Until this point, most studies have focused on mercury in fish and fish-eating birds in aquatic environments. These new findings, however, show that animals in non-aquatic habitats also have elevated mercury levels. One of the project's most significant discoveries is the presence of mercury in terrestrial, mountain-dwelling songbirds like the Bicknell's Thrush. This rare species, which VINS has studied closely since 1992, nests almost exclusively in high elevation forests of the northeastern U.S. and Canada , and winters in the Caribbean Greater Antilles. VINS's data, reported in the Ecotoxicology volume, reveal that Bicknell's Thrush and other songbirds in Vermont 's Green Mountains are accumulating mercury, and that nearly all of it is in the toxic methyl form.

VINS's research on mercury in Bicknell's Thrush will continue, as scientists attempt to trace the specific pathways by which songbirds accumulate mercury, and the synergistic effects that mercury and other environmental stressors like acid rain may have on terrestrial bird populations. VINS looks forward to being closely involved in future studies that will shed crucial light on the risk that mercury poses to ecological health.

Download the latest findings

Ecotoxicology Mercury Special Issue: 21 scientific papers describing the latest mercury findings.

Mercury Connections: The extent and effects of mercury pollution in northeastern North America (a new report that summarizes the information in the Ecotoxicology journal papers,)