La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	[The importance of second broods for the reproductive success in the Coot (Fulica atra)]
Auteurs :	Jochen Bellebaum, Auteur
Type de document :	Article
Dans :	Vogelwarte (40(3) November, 2000)
Article en page(s) :	198-205
Langues:	Allemand
Résumé :	Seasonal occurence and success of first and second broods were investigated in two Coot populations in Westphalia (North-West Germany) 1992-1995. In the seminatural Lippe valley second broods occurred only in one of three years. Among the population in the Ruhr valley, 10-33 % of the breeding pairs started a second brood, presumably due to high winter temperatures and productivity of the breeding habitat (sewage pond). Mean breeding success (fledglings per territory and year) in the Ruhr valley was lowest in territories without double broods. In territories with double broods in two years, on average twice as many young fledged in the first brood as compared to territories without double broods. Also, most second broods were successful. In territories with only one double brood success was intermediate in the first and zero in the second brood. In high quality territories pairs were able to maximize their reproductive output by a second brood after a high success in the first brood. These adults are thought to be of high individual quality. The result confirms the quality hypothesis. Double broods did not compensate for a low success of early first broods as expected under the date hypothesis.

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