The breeding range of the Common Eider (Somateria mollissima dresseri) has been expanded south of its traditional range through the use of transplanted birds. Originally introduced to one coastal island in southeastern Massachusetts in the 1970s, eiders spread out to other islands and now ≥870 eiders nest on more than 20 islands along the Massachusetts coastline from Cape Ann to Boston Harbor to Buzzards Bay and may be further spreading south.