More than 90% of the breeding population (85-105 bp in 1998-2000) is located on the Wadden Sea islands, with up to 38 bp at Terschelling. Inland breeding is merely confined to the Oostvaardersplassen area in Zuidelijk Flevoland (4-5 bp), with only accidental breeding records elsewhere. Compared to 1973-77 (100-130 bp), inland breeding has almost disappeared, as marshes in the newly reclaimed polder Zuidelijk Flevoland have been cultivated. Breeding elsewhere had already vanished by 1970. The population on the Wadden Sea islands is gradually declining since the early 1990s, probably because of low productivity.