Long-term population trends and shifts in distribution of Bewick’s Swans Cygnus columbianus bewickii wintering in northwest Europe

Coordinated international censuses of the Northwest European Bewick’s Swan  Cygnus columbianus bewickii null population have been undertaken across the swans’ wintering range at c. 5-year intervals since 1984. During the early years of the study, numbers increased steadily to a peak of 29,780 individuals in January 1995, but then declined by 39.4% to 18,057 swans counted in January 2010 before showing a partial recovery to 20,149 recorded in...