Confirmed breeding was reported in only 14 atlas squares. The interpretation of the other records is difficult, since many pairs summer in suitable breeding habitat. Most records originate from the lowlands, e.g. around Lake IJsselmeer and the Rhine valley. Detailed observations suggest that breeding output is low, perhaps as a result of a mismatch between the breeding cycle and food availability. In 1998-2000 perhaps some 20-30 bp were present, apart from some tens of non-breeding pairs. Comparison with earlier surveys is difficult because of changing observer-efforts and poor documentation of many breeding records.
- 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.