Due to the completion of a series of water reservoirs in the late 1950s, the Vltava River has stopped freezing over in Prague. This attracts a lot of wintering waterfowl and other water-bird species. Their numbers and seasonal dynamics have been periodically monitored since the 1970s. The wintering water-birds’ numbers increased from the 1970s and peaked in the 1990s. Since that time, however, they have again been on the decrease.
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© J. Mourková