During June and July 2007, a team of biologists from Rachel Carson National Wildlife Refuge and BioDiversity Research Institute, in partnership with Parker River, Chafee, and Long Island National Wildlife Refuges developed a geographic exposure profile of methylmercury exposure in salt marsh sharp-tailed sparrows.  Blood samples were collected for mercury analysis from 52 saltmarsh sharp-tailed sparrows in Furbish Marsh in Maine and from an additional 150 birds at the other refuges.  The goal of the study was to evaluate the levels of methylmercury (MeHg) available to these insectivorous birds.  Previous studies indicate that birds breeding in Maine, Massachusetts and Rhode Island have elevated mercury levels in their blood.

            The saltmarsh sharp-tailed sparrow is considered globally vulnerable to extinction and is one of the top priority species for conservation and management within Bird Conservation Region 30.  Since exposure to MeHg can have detrimental effects on bird physiology, behavior, and reproductive success, it is extremely important to monitor and reduce levels of this harmful substance.    Saltmarsh sharp-tailed sparrows spend their entire lifecycles inhabiting the marsh ecosystem, they serve as ideal indicators of mercury contamination. 

            In order to conduct the survey, mist nets were placed along drainage ditches and tidal creeks.  Teams of approximately 8 people formed semicircles and gradually moved inwards, 'herding' the birds towards the nets.  In addition to taking blood samples, biologists banded each bird and recorded measurements, sex, and weight.  All birds were released unharmed.