Spaanse Kokmeeuwen in Noord-Nederland

This paper presents an overview of records in The Netherlands of Black-headed Gulls Larus ridibundus that were ringed in Spain. The records were derived from.annual reports of the Spanish Ringing Centre (1986-2007), from a file of Vogeltrekstation Arnhem (northern part of The Netherlands, 1950-2008), and from files of.birds colour-ringed in Barcelona and in Salamanca, supplemented by observations of bird-watchers. All records concerned birds ringed in Spain outside the breeding season. No birds were reported from Drenthe and six were reported from the province of Groningen. Six birds from Barcelona (blue colour-rings) and three birds from Salamanca (yellow colour-rings) were seen in The Netherlands. The records in The Netherlands can be divided into four groups: (1) breeding birds; (2) moulting birds; (3) passage migrants; (4) winter visitors. There were two cases of confirmed breeding: a bird trapped on the nest in Leeuwarden in 2000 (ringed near Madrid in December 1994), and a bird seen with small chicks in a breeding colony at Tholen in 2006 (ringed near Madrid in November 1991). Besides, breeding was very likely for an adult in a breeding colony at Hompelvoet (1 May 1996), for an adult seen at the rubbish dump near Bergen op Zoom (30 May and 12 June 1997), and for three adults seen in May in the breeding colony at Zwillbrocker Venn in Germany (birds of this breeding colony also forage in The Netherlands). Breeding was likely for several other records as well, including for at least five birds from the northern part of The Netherlands. There were at least seven birds recorded during the period of wing moult, including individuals seen in different years at Lauwersoog (2012 and 2013) and at Oude Zeug (2011, 2012, 2013). It seems likely that such birds spend the period of primary moult in The Netherlands and that they winter in Spain. There was no information about their breeding areas. There were a few records of passage migrants during spring and (late) autumn, including a bird seen by the same observer in Arnhem on 29 February 2000 and in Copenhagen on 20 March 2000. There were almost no records of birds wintering in The Netherlands, despite intensive ring reading activities throughout the country in this period of the year. An exception to this rule was a record in January-February 2012 in Leiden and Voorburg (photos 2, 3). All in all, the results revealed that birds with Spanish rings in The Netherlands either concern local breeding birds or birds breeding in countries around the Baltic Sea. There are many recoveries in Spain of birds ringed as chicks in The Netherlands (summarized in Speek & Speek 1984), but almost all concerned birds reported dead. The situation has changed dramatically, as the large majority of the records in my paper concern sightings of birds seen alive, in quite a few cases of birds with several sightings. There were also several records with additional information, about breeding status for instance. The change is due to a strong increase in ring reading activities (often combined with taking pictures), together with an increase in colour-ringing activities. This enables us to get a much better understanding of movements, behaviour and status of individual Black-headed Gulls.