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In 2008, we concluded the 6th and final year of what was originally designed as a 5-year study to examine survival, recruitment and recovery rates of nesting common eiders (Somateria mollissima dresseri) on Flag Island, Harpswell, Maine. The total breeding population of common eiders on Flag Island was estimated to be about 500 nesting pairs in 2008, which is at the long term estimate of approximately 500-600 nesting pairs for this island. Both the 2007 and 2008 nesting estimates were, however, a marked improvement from the 2006 estimate when only 200 hens actually nested. This low point coincided with the beginning of significant non-nesting events by hen eiders in east Casco Bay at and leading up to two significant mortality events on the wintering grounds in Massachusetts. One cause contributing to these die-offs was determined to by an RNA virus. Nest success over the duration of this study was high at 75% in 2005, 74% in 2006 to 89% in 2007. Although the percentage of nesting great black-backed gulls increased during this investigation, the overall size of the nesting gull population remained fairly constant.


Birds; Habitats, Islands; Monitoring Species


Casco Bay watershed, Harpswell



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