Abstract
The rivers in České Budějovice are the most important wintering site for waterbirds in the South Bohemian region. This is the first study which summarises knowledge about this locality.
There were 43 waterbird species recorded on flowing water in České Budějovice and on Mladé sludge lagoon during the winter half of the year (October-March) in years 1993-2012. There were 38 waterbird species recorded during "real winter months" (December, January, February).
On average around 600 individuals waterbirds winter in the studied area; their abundance has declined by 32% during the last 20 years. Little Grebe, Mute Swan, Common Pochard, Tufted Duck and Common Coot are all declining species.
However numbers of Great Cormorant and Common Merganser have increased. Mallard, Mute Swan and Common Coot (also Black-headed Gull in early spring) are dominant species in the studied area.
The abundance of all species (in which it was possible to determine the temperature dependence) except Grey Wagtail have increased in response to a decline in air temperature during winter. The River Vltava is the most important locality in the studied area for wintering water birds.
Detailed species commentaries are supplemented with ethological notes.