Excreta samples were collected from the marine ducks' nesting area near islands. Analysis of the samples has shown that the diet of the species consisted mainly of benthic invertebrates. Mollusks and arthropods were the greatest group. Common mussels Mytilus edulis were found in all samples. Quite possibly, the poor identifiability of digested remains may have resulted in underestimating of Polychaeta and crustacean shares in the Eider diet. Eider foraging strategy is usually targeted at the most numerous benthos groups in the study area such as mollusks and crustacea. The diet of Common Eider in summer consists almost exclusively of intertidal and shallow.water invertebrates – intermediate hosts of richest parasite fauna.