Winter distribution of Whooper Swans Cygnus cygnus cygnets bred in Latvia, 2004-2008

摘要

Of 396 Whooper Swan Cygnus cygnus cygnets marked with neck collars in Latvia during the 2004-2008 breeding seasons, 70% were re-sighted at least once in winters 2004/05-2009/10. Overall, 91% of the 2,985 winter re-sightings were of swans seen in Germany, 5% were in Poland and the remaining 4% were distributed across Latvia, Lithuania, The Netherlands, Sweden, Denmark, France, Switzerland and Austria. The main wintering areas, situated 760-840 km from the ringing sites, were along the Rivers Elbe andOder in inland northeast Germany and in neighbouring parts of Poland. The annual proportion of swans marked in Latvia which were re-sighted wintering in this region ranged from 41-80%. The maximum distance between the ringing and wintering sites recordedfor each bird averaged 836 km (s.d. +-169 km, range = 407-1,518 km). The average distance between the ringing and wintering sites correlated with winter severity, particularly amongst swans in their second winter or older.