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Institut de recherche pour la conservation des zones humides méditerranéennes

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Titre :	Development of a moult migration, and flight-feather moult in Ferruginous Ducks Aythya nyroca from Central Europe.
Auteurs :	Peter Koehler, Auteur ; Eberhard von Krosigk, Auteur
Type de document :	Article
Dans :	Vogelwarte (44(2) MAY 2006)
Article en page(s) :	113-121
Langues:	Allemand
Résumé :	A moult migration in Ferruginous Ducks is described for the first time. The tradition to moult off the breeding grounds began in 1956 in the Ramsar site "Ismaninger Speichersee mit Fischteichen", near to Munich, Upper Bavaria. This development coincided with the collapse of a small breeding population 170 km north. From 1975 to 1993 eight (three to twelve) birds moulted their flight-feathers here each year. Following a shift in the trophic state of the ponds from hypertrophic to polytrophic, numbers decreased in 1994, but then recovered with a significant reduction of carp Cyprinus carpio densities. Sixteen, six, and fourteen specimens were found moulting in 2000 to 2002. The phenology of moulting birds and wing moult was studied in 58 individuals between 1997 to 2002. The first birds arrived three weeks prior to the median. The third quarter of male birds arrived one week after the median. Sixteen out of 29 males arrived between 27.6. and 12.7. Eight out of 17 female arrivals are concentrated in the last 11 days of the 44 day arrival period, between 19.7. and 30.7. Some birds arriving early drop their wing-feathers only after 24-31 days; birds arriving later take no more than 15 days. Thirty-two of 36 males and six early females dropped their wings between 5.7. and 27.7. Late arrivals follow within

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