In March 2006 more than one thousand eider ducks ( Somateria mollissima) were feeding on the American razor clam Ensis directus in the Dutch Wadden Sea near the southern part of the island of Texel. This could be detected from analysis of their faeces deposited on the dike, which consisted mainly (90%) of fragments of this shell. About 10% of the fragments larger than 0.5 mm consisted of remains of the exoskeleton of the shore crab Carcinus maenas. In former times their main food in this area consisted of mussels and cockles with a few crabs (Swennen, 1976; Cadée, 1994). Mussels and cockles are here apparently no longer available in sufficient numbers for the eider ducks.