Artikel-Suche

Felix, K. & L. Felix

Der Mittelsäger Mergus serrator auf dem Zürichsee in den Wintern 1990/91 bis 2009/10.

2012

109

95–100

Key words
(von 1994 bis 2006 vergeben)

Winterbestand, Zunahme

Schlagwort_Vogelart
(wissenschaftlich)

Mergus serrator

Schlagwort_Vogelart
(deutsch)

Mittelsäger

Horgen, Wädenswil, Zürichsee

deutsch

Abhandlung

The Red-breasted Merganser Mergus serrator on Lake Zurich in the winters 1990/91 to 2009/10. – In the 20 winters from 1990/91 to 2009/10 we regularly observed along the shore of Lake Zurich in the sector Horgen–Wädenswil (about 6 km). Redbreasted Mergansers Mergus serrator were most often present between the end of November and the beginning of March. The proportion of recognisable males was 25 %. Each winter we recorded Red-breasted Mergansers on average on 9 occasions with a mean sum of maxima per five-day period of 13. Since the winter 2004/05 observations increased markedly to 8–33 per winter, with sums of maxima per five-day periods of 13–55. Thus wintering numbers in the sector Horgen–Wädenswil have become more important than those of the sector Rapperswil–Jona, formerly the most important part of Lake Zurich for the species. The increase is not seen in the results of the waterbird census of mid-November and mid-January on Lake Zurich. It is however consistent with the increase of Red-breasted Merganser numbers in the whole of Switzerland in mid-January.