Regular wintering of Great Cormorant Phalacrocorax carbo sinensis in the Czech Republic was recorded from the mid 1980s. In the 1940s to 1960s, no wintering Cormorants were recorded in the Czech Republic.
Furthermore, wintering population size was estimated at 500 - 1,500 individuals in 1982 - 1985, respectively 4,000 - 6,000 individuals in 1999 and more recently at 10,000 - 11,000 individuals in January 2005 - 2007.