La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Age composition of wintering rooks Corvus frugilegus.
Auteurs :	Till Topfer, Auteur
Type de document :	Article
Dans :	Vogelwelt (Die) (125(1) 2004)
Article en page(s) :	53-58
Résumé :	This paper describes the proportion of adult and young Rooks Corvus frugilegus in wintering flocks. Based on field observations in the area of Dresden/Saxony an average proportion of only 4.7% juveniles was observed from 1998 to 2002. Most of the flocks included less than 10% juveniles, nearly 40% of all flocks consisted entirely of adults. This small amount of juveniles may indicate a decreasing reproductive success in the breeding areas in Poland and Russia. Results from other studies as well as census problems are discussed regarding their applicability for estimations of population development.

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