The status and distribution of the Mute Swan Cygnus olor in the USSR: a review of recent censuses
The present status of Mute Swans in the USSR is characterised by a tendency for the numbers and range of the species, which had in the past contracted, to be re-established. In order to monitor these processes All-Union counts of the numbers of breeding and moulting Mute Swans have been carried out in recent years. With the first, rather incomplete, count of 1974 it was established that there were 4,300 breeding pairs and 29,300 non-breeding birds. In the second, more complete count, in 1978, 7,700 breeding pairs and 43,100 non-breeding birds were counted. The total numbers in 1987 were 22,000 breeding pairs and 240,000 non-breeding birds; ie. there were about 284,000 swans in the spring of that year and no less than 350,000 birds by the end o f the breeding season. The process of re-establishment of numbers and ranges of Mute Swans in the USSR is far from complete. There are areas where the species, after disappearing, has not reappeared even though conditions are favourable. At the same lime, the population density has not reached the maximum possible indices. The process of further recolonization of Mute Swans in the USSR will continue, if favourable living conditions are conserved in the principal breeding grounds, from which there is a constant dispersal.
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