The Czech Republic, as an inland Central European country, is not part of the core wintering area for most duck species in the Western Palearctic. Nevertheless, interseasonal changes in numbers and distribution of particular species are recorded, which may reflect climatic fluctuation.
Waterbird counts were carried out annually at 48–639 wetland sites in the Czech Republic in 1966–2008, as part of the International Waterbird Census (hereafter IWC). These data were used to assess longterm trends in the number of duck wintering in the Czech Republic for the 15 most abundant species.