Wintering Range of the Blackcap (Sylvia atricapilla) in Europe - Stabilized or Changing?

Abstract

Wintering Range of the Blackcap (Sylvia atricapilla) in Europe - Stabilized or Changing? So far the expansion of the Blackcap wintering range could not have been confirmed based on the analysis of ringing recovery data. The aims of this work was to define present boundaries of regular wintering area of the Blackcap in Europe and to find out whether the wintering range of the species has expanded over the last decades. A comparison of the Blackcap return rate in different parts of wintering area in subsequent winters was based on the probability distribution analysis. Dates of the Blackcap recoveries in different areas were also compared. Changes in number of winter recoveries from Great Britain as well as from regions to the north and south of the delimited northern boundary of the species regular wintering area were analysed as well. Blackcaps ringed in winter in Scandinavia did not return to this area in the following winters. Percent share of such individuals in Central-Western Europe was low. Birds were recorded in these regions mainly at the beginning of winter. The Blackcap return rate both in Great Britain and in southern Europe was very high; birds were observed there throughout the whole winter. Over the last decades of the XXth century the numbers of winter recoveries grew to a similar extent in the areas located to the north and south of the northern boundary of the Blackcap regular wintering area. Only in Great Britain this increase was faster. Based on the ringing recovery data analysis it can only be concluded that the regular wintering area of the Blackcap in Europe is most probably limited to the territories of the Mediterranean Sea basin. Most winter recoveries from other parts of Europe are probably only unsuccessful wintering attempts.