Most pairs breed in colonies of Black-headed Gull. The Delta area holds over 90% of the Dutch population and several colonies of over 100 bp (largest at Hellegatsplaten, 334 in 1998). Elsewhere, only one colony exceeded 10 bp. Population growth since the 1970s (7-8 bp in 1973-77) was spectacular: 10 bp in 1980, 92 in 1990 and 416, 475, 850 and c. 1150, respectively, in 1998-2001. High breeding success (especially when compared to Black-headed Gull), high survival of adult and immature birds and immigration may account for this increase. Ringing has shown close links with the Belgian population and, to a lesser extent, with colonies elsewhere in Europe.
Meininger, P. L.
- 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.