With the exception of birds sampled in Plum Island Sound, MA, concentrations of total mercury were relatively low and were similar to mean values reported for eiders in other locations. Mean mercury levels in eiders from Plum Island Sound were nearly three times higher than any blood mercury concentrations reported for common eiders. Blue mussels and periwinkle snails from Boston Harbor, MA, were significantly higher in mercury than those from Plum Island Sound and locations in Maine. We found a consistent relationship between mercury levels in eider blood and food items in Maine and Plum Island Sound, MA, but not in Boston Harbor. This may suggest that eiders in Boston Harbor are selecting a different food source than blue mussels in that area. With our next research steps, we hope to use stable isotope analysis to help determine differences in food sources and foraging strategies in these different locations. Key findings from this study have recently been accepted for publication in Marine Pollution Bulletin (Meattey et al. 2014, Marine Pollution Bulletin, in press).