La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Breeding numbers of the Black-headed Gull Larus ridibundus in Germany 1963-1999.
Auteurs :	Jochen Bellebaum, Auteur
Type de document :	Article
Dans :	Vogelwelt (Die) (123(4) 2002)
Article en page(s) :	189-201
Résumé :	The first national census of breeding Black-headed Gulls in Germany was undertaken in 1999 and the results were compared to earlier partial counts. A total of 151,400 pairs was counted in 305 colonies, showing a decline of about 25% since 1988, when about 202,300 pairs were estimated. Only in the Wadden Sea breeding numbers remained stable. The strongest decline was recorded along the Baltic Sea coast with -75% since 1983. The total number of colonies remained nearly constant. Colonisation of man-made habitats increased strongly after 1950. This and the fact that more than 80% of the population now breed in nature reserves suggests that there is no large-scale lack of breeding habitat limiting population size. The species' decline in large parts of Europe can be explained by food shortage during the chick-rearing period, due to intensive agricultural land-use, a factor which does not play a role in the Wadden Sea. Simultaneous large-scale counts of breeding pairs are an appropriate method for further monitoring of this species and should be repeated in future.

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