Dense distribution in the eastern half of the country, where thriving populations occur in urban areas and farmland with scattered buildings. Densities in built-up areas are probably underestimated due to insufficient coverage by field workers. Strong west- and northward expansion in the past decades, but in the newly colonised areas only relatively small numbers are involved. Trends and population size are difficult to assess due to lack of data from urban areas. Estimated population in 1998-2000 is about 27,000-37,000 bp.
- 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.