Józef Witkowski, Beata Orłowska
Ornis Polonica 2012, 53: 1–22
https://doi.org/10.12657/ornis.2012.1.0
Abstract: The paper describes changes in abundance of breeding bird species of the biggest in Poland fish breeding ponds (6,500 ha) in the Barycz River Valley over last 15 years. Since previous work has been published in 1995, no significant habitat changes took place in the area. Among all 180 breeding bird species in the Barycz River Valley, changes in numbers of 24 waterbirds were noted. 13 species declined (three species of grebes Podiceps sp., Great Cormorant Phalacrocoarx carbo, Grey Heron Ardea cinerea, White Stork Ciconia ciconia, Greylag Goose Anser anser, Tufted Duck Aythya fuligula, Marsh Harrier Circus aeruginosus, Little Crake Porzana parva, Coot Fulica atra, Sand Martin Riparia riparia and Common Rosefinch Carpodacus erythrinus). Common Crane Grus grus increased strongly, while Ferruginous Duck A. nyroca and Little Bittern Ixobrychus minutus are slowly increasing in numbers. Numbers of newly breeding species – Whooper Swan Cygnus cygnus, Goldeneye Bucephala clangula and Whiskered Tern Chlidonias hybrida – are either stable or increasing. Two other recent colonisers – Caspian Gull Larus cachinnans and Mediterranean Gull L. melanocephalus – are still very scarce.
