(* = Kurzbeitrag)
Vom Wintergast zum regelmässigen Brutvogel: Brutbestand und Verbreitung der Kolbenente Netta rufina in der Schweiz.
(von 1994 bis 2006 vergeben)
Brutnachweis, Bestandsentwicklung, Brutbestand, Verbreitung, Brutbiologie, Schlüpftermine, Mischbruten, Brutphänologie, Winterbestand, Überwinterungsgebiet, Seen, Flüsse, Flussstaus, Kleingewässer
Netta rufina, Aythya fuligula, Anas platyrhynchos, Aythya ferina, Somateria mollissima
Kolbenente, Reiherente, Stockente, Tafelente, Eiderente
Schweiz, Deutschland, Bodensee, Neuenburgersee
From wintering to breeding: abundance and distribution of breeding Red-crested Pochards Netta rufina in Switzerland. The Red-crested Pochard Netta rufina colonised Switzerland in the 20th century. In 1927 the first nest was found in the Swiss part of Lake Constance (Bo densee), ten years after the first breeding records on the German side. Until 1964, when the first brood was confirmed on Lake Zurich, breeding was restricted to Lake Constance. Until 1980 breeding records in Switzerland remained scarce but since then breeding has been confirmed every year. In the 1990s a rapid increase started, reaching 222 confirmed broods in 2011. The number of breeding pairs for this year was estimated at around 450. The increase happened in parallel to the massive increase in wintering numbers from a few hundred in the mid-1980s to a maximum of over 30000 in 2009. Redcrested Pochards breed mainly on the large lakes of the Swiss plateau, with the highest numbers on sites where wintering birds concentrate. Apart from isolated records on Lac de Joux at 1000 m a.s.l., breeding is restricted to lowland areas (below 600 m). Lake Neuchâtel, leading the list of the most important wintering sites together with Lake Constance, holds around half of the Swiss breeding population. In the last decade, the species has increasingly spread to small waterbodies. Data collected by volunteers give an insight into the breeding biology, although no systematic sampling has taken place. The Red-crested Pochard has a long breeding season. Hatching dates were recorded between the end of April and beginning of September, with an overall peak in July. Records of clutches on Lake Neuchâtel, where Red-crested Pochards nest mainly on artificial islands, indicate a high degree of interspecific nest parasitism, in particular with Mallard Anas platyrhynchos, the most abundant breeding duck species in Switzerland. Mixed families were commonly recorded as well. In most cases these were led by females of other species, mostly Mallard (80 % of 219 families from across Switzerland), followed by Tufted Duck Aythya fuligula (16 %), Common Pochard A. ferina (3 %) and Common Eider Somateria mollissima (1 %). Only in seven cases were ducklings from other species led by a Redcrested Pochard female. In six of these cases the family contained ducklings of Tufted Duck, in one of Mallard.
PDF Dokument (öffentlich)
PDF Dokument (registrierte Mitglieder)