High densities are characteristic for the coasts in the north and southwest of the country. Inland breeding is mainly confined to coastal, somewhat saline farmland and the river area. Since 1973-77, an inland expansion occurred, resulting in probably self-sustaining populations here. In the coastal dunes, numbers dropped since the early 1980s, coinciding with the near-disappearance of rabbit populations (decline of available nestholes) and atmospheric deposition (adverse foraging conditions for downy young). Breeding population of 5000-8000 bp in 1998-2000 and several 1000 non-breeding pairs (in some areas 25-50% of the total population).
- 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.