Acta Zoologica Cracoviensia, 24 (1979 - 1980)
Nesting of Rooks Corvus frugileus Linnaeus, 1758, in the Cracow Area
Abstract:
During nine-year observations of Rooks breeding in the Cracow area (230 sq. km) their number was found to have been reduced to 30 rookeries and 1082 nests. Most of the nests (66%) belonged to five rookeries set up in manorial parks before they had been incorporated in the town area in 1941; the other ones were situated in regions already built up, less than 20 sq. km in area. The following factors are conducive to the formation of rookeries: 1. a rich macrofauna in the rhizosphere, even if rather distant from the nest, nest, 2. the presence of trees with suitable crowns, 3. easiness of access from the air and 4. the nearness of buildings. Some internal and external stimuli which govern the behaviour of Rooks in the breeding season are discussed and so are the measures for preventing them from nesting.
