Changes in Numbers and Distribution of Wintering Waterfowl Populations in Lithuania in the 20th Century

Changes in numbers and distribution of wintering waterfowl populations in Lithuania in the 20th century are assessed and their reasons analysed. A total number of wintering waterfowl species increased from 17 in the 1900s–1940s to 28 in the 1960s and to 42 in the 1990s. A total number of wintering wildfowl species doubled. In the 1930s, several thousand wintering waterbirds were recorded throughout the Lithuanian wetlands. In the late 1990s, about 150,000 wintering waterbirds were annually counted on coastal wetlands and about 50,000 of them – on inland water bodies. Major changes observed in species composition and in the abundance of wintering waterfowl in Lithuania were primarily caused by the human activities affecting waterbird habitats and by general climatic amelioration, an increased number of mild winters in the Eastern Baltic region in recent decades.