Population trends of the Mute Swan Cygnus olor in the Palearctic

Abstract

The Mute Swan is widely distributed in the Palearctic. The west and central European populations are still increasing both in numbers and in range. Their ranges are now almost continuous. There are about 28,400 breeding pairs in Europe and about 152,500 birds wintering. Because not all wintering areas are censused, the number o f wintering swans may be under-estimated by 15%, so the total may be closer to ±175,000. The increase in numbers and the extension o f the range are coupled with changes in behaviour and choice of nesting sites. Some birds from the eastern part of the range have ceased to migrate to wintering grounds and remain in their breeding areas. In south eastern Europe and Asia, where the distribution of swans is continuous, their increases in numbers and range extension have been even more marked. The total number o f birds in the USSR population (without swans from Baltic republics) was about 325,000 in 1987 (Krivonosov in press, recalculated). The ranges of eastern and western populations overlap in south eastern Europe. The total number of Mute Swans in the Palearctic is estimated to be about 500,000 individuals. The main reasons for changes in swan numbers are discussed.