CHANGES IN ABUNDANCE AND SELECTION OF FORAGING HABITAT IN CORMORANTS PHALACROCORAX-CARBO IN SOUTH BOHEMIA (CZECH-REPUBLIC)

The breeding population of the Cormorant Phalacrocorax carbo sinensis in south Bohemia increased since its establishment in 1983. However, n umbers of breeding pairs began to decrease after 1988. The relationshi p between Cormorant numbers during the breeding season and habitat and fish stock characteristics was investigated on 197 ponds in Trebon La ndscape Protected Area. Out of 749 Cormorants recorded, 92.3% were obs erved on (1) ponds located in distance less than 10 km from the breedi ng colony, and (2) ponds with water surface area larger than 20 ha. Th e Cormorants preferred ponds with water depth of 1-2 m, surrounded by wood and well developed shore line. 87% of Cormorants occurred on pond s with Carp Cyprinus carpio older than 1 year. Among ponds without bre eding colony, the Cormorants prefer fish sized between 100-200 mm.