Kleptoparasitism by skuas, particularly the great skua, occurs at breeding sites. Similar problems occur, of course, with extralimital claims of great skua. In the eastern North Atlantic, it is replaced by the great skua. The SPA designation lists six priority species&colon; fulmar, great skua, guillemot, kittiwake, and razorbill. Predation by the great skua ("Catharacta skua") is also reduced by several birds arriving simultaneously. The great skua ("Stercorarius skua") is a large seabird in the skua family Stercorariidae.