Scandinavian/Baltic Mute Swans Cygnus olor in the Netherlands: movements under the influence of severe winter weather and their consequences

Abstract

The Mute Swan is believed to be mainly a sedentary bird. North-west Europe holds seven separate groups. So far, only incidental movements of individuals between groups have been described. Data on winter movements of Scandinavian-Baltic birds were presented. This phenomenon occurs mainly during severe winters, but the origin of winter visitors differs between years. Based on observations, ring data and information on the weather in the areas concerned, an attempt was made to describe and explain the differences between winters. Some o f the winter visitors stay and settle in the local breeding population. An evaluation of the importance (numbers moving versus staying) and the effects (return versus settle, genetic exchange) on a population level was given.