Dynamics and age structure of wintering Mute Swans Cygnus olor in south-eastern Poland

Abstract

This paper deals with number and distribution o  Mute Swans during four consecutive autumn-winter seasons (October-March 1985-1989) in south-eastern Poland The number of wintering Mute Swans is still increasing. In 1989, 2,497swans were recorded, about 13% of all Mute Swans wintering in Poland. Two important winter haunts are described which contain about 80% of all swans. They differ in the pattern of arrival and percentage of young birds. The urban winter sites have more young birds than the rural ones. The duration of stay at the urban winter site is also much shorter. The percentage o f young birds in south-eastern Poland is similar to that in Great Britain and Sweden but it is distinctly lower than values reported in USA and southern USSR. Most swans come to these winter haunts from other parts of Poland but birdsfrom East Germany, Czechoslovakia and Denmark were also noted. Percentage of Polish morph is very low (1-3%), similar to the rest of Poland.

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