La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Population biology of a Common Tern Sterna hirundo colony
Auteurs :	Helmut Wendeln, Auteur ; Peter H. Becker, Auteur
Type de document :	Article
Dans :	Vogelwelt (Die) (119(3-5) 1998)
Article en page(s) :	209-213
Résumé :	Since 1992 we perform a long-term population study of Common Terns breeding in the harbor area of Wilhelmshaven, German Wadden Sea coast. We use subcutaneously injected passive transponders for life-long individual identification. All fledged chicks and selected adults caught on their nests were marked enabling annual identification without retrapping. Return rate of adults was on average 89%, whereas only 33% of fledged chicks returned to the colony site. 76% of prospectors returning for the first time to the native colony site were two years old, 21% were three years old. First breeding attempts occurred mostly in the age of 3 years (70%), but in most cases were unsuccessful. The observed mortality rates show that in this colony a breeding success of 0.85 chicks cntdot pair-1 cntdot year-1 is sufficient to keep the population size constant. As the recorded breeding success is 1.3 chicks cntdot pair-1 cntdot year-1, this colony is increasing at a rate of 5.9% annually.

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