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Krummenacher, B., M. Weggler, D. Schmidt, K. Bollmann, D. Köchli & K. Robin

Wie gross sind die Chancen für eine Wiederansiedlung des Fischadlers Pandion haliaetus in der Schweiz?

2009

106

165–180

Key words
(von 1994 bis 2006 vergeben)

historische Verbreitung, Bestand, Bestandesentwicklung, Modellierung, potenzielles Brutgebiet und potenzielles Horstareal, Brutperiode, Übersommerung, Wiederansiedlung, Nisthilfen

Schlagwort_Vogelart
(wissenschaftlich)

Pandion haliaetus

Schlagwort_Vogelart
(deutsch)

Fischadler

Mitteleuropa, Schweiz, Schaffhausen, Bodensee, Hochrhein, Zürich, Aargau

deutsch

Abhandlung

Perspectives for a re-colonisation of Switzerland by the Osprey Pandion haliaetus. – The Osprey formerly inhabited Switzerland possibly in considerable numbers before heavy persecution started in the 19th century or even earlier. The last successful breeding was recorded in 1911, the last nest-building activities in 1915. To determine the potential for a re-colonisation of Switzerland, we assessed the present availability of breeding habitat, the current population dynamics in Europe, and the frequency of Ospreys passing the summer in Switzerland since 1980. We identified the potential suitable areas within Switzerland by a simple habitat model. In the model we evaluated the distribution of lakes and rivers, forest, dispersal distance of the species and indirect sources of disturbance. Considerable breeding habitat is still available along rivers and lakes in the lowlands. However, today many shores are built-up or heavily used for recreational purposes. Osprey populations in Germany and France have been growing considerably since the eighties. At the same time, single non-breeding Ospreys can be observed in summer in Switzerland. The edge of the contiguous range in northern Germany currently shifts southwards with an approximate speed of 10 km per year. Although the conditions for a re-colonisation of Switzerland by Ospreys seem to be fulfilled, the nearest breeding pairs are still 300–360 km away from Switzerland (to the northeast in Bavaria/Germany and to the northwest in Loiret/France). To accelerate and facilitate a natural re-colonisation of Switzerland, we propose to set up artificial eyries. They should be built on exposed trees and on top of power transmission poles within the identified breeding habitats within the next years.