Breeding is mainly confined to the old deciduous forests of the east and centre of the country and the inner dunes. The distribution in the northeast and south has expanded remarkably since the 1970s, due to maturation of woodland, but densities here are generally inferior to those in the core areas. The reclaimed polders Noordoostpolder and Oostelijk Flevoland became colonised in the 1980s. The population in 1998-2000 is estimated at 16,000-20,000 bp (5000-6000 in 1973-77).
- 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.