Most colonies are situated in marshes and lower grasslands on peat soils in the northeast and west of the country, and in the eastern river district. Colonies nowadays are generally small, exceptionally ranging up to 130 bp (northwest Overijssel). Since the 1950s, disappearing floating vegetation, declining food resources and increasing disturbance resulted in a strong population decline (from more than 15,000 bp in the 1950s to 3500-4500 in 1973-77 and 1000-1250 in 1998-2000) and range contraction. Lack of nest-habitat was only partially compensated by providing artificial nest platforms, nowadays used by 80% of all pairs.
Winden, J. van der
- SOVON Vogelonderzoek Nederland 2002. Atlas van de Nederlandse broedvogels 1998-2000. Nederlandse Fauna 5: 1-584. Nationaal Natuurhistorisch Museum Naturalis, KNNV Uitgeverij & European Invertebrate Survey-Nederland, Leiden.