A fairly late breeding attempt of Sandwich Terns (400 pairs) and Black-headed Gulls on a small island in Flaauwers Inlaag (Schouwen, Zeeland) failed mostly as a result of egg and predation of a single, specialised Mediterranean Gull in 2009. It is concluded that the chances for the Mediterranean Gull were enhanced due to a lack of experience of these late-nesting birds.