Tomasz Wilk, Rafał Bobrek, Aleksandra Pępkowska-Król
Ornis Polonica 2019, 60: 103–123
https://doi.org/10.12657/ornis.2019.2.2
Abstract: To determine the significance of dam reservoirs of the Polish Carpathians for migrating and wintering waterbirds, monthly bird counts were conducted on the 12 largest reservoirs from August to March in the years 2011–2015. In total, 239,501 individuals of 75 waterbird species were recorded during 4 seasons. The most numerous species was the Mallard Anas platyrhynchos (41.2% of all birds), and the group of dominants included also the Common Gull Larus canus, Black-headed Gull Chroicocephalus ridibundus, Caspian Gull L. cachinnans, Great Cormorant Phalacrocorax carbo, Tufted Duck Aythya fuligula, Mute Swan Cygnus olor and Coot Fulica atra. The average number of individuals observed during a single count on all reservoirs was 7,983. Usually less than 1,000 birds were found during a count on a single reservoir, and the highest numbers reached 4–6 thousands on the Żywiecki, Dobczycki and Czchowski reservoirs. The assemblage of waterbirds reached the highest numbers in November–January, and peaked in December. Much more birds were recorded during mild winters (up to 12,484 birds in January 2014) than in colder ones. The regional importance of the Carpathian dam reservoirs for waterbirds is high, especially for Mute Swan, diving ducks, mergansers, gulls, Coot, and Great Cormorant. At a national scale, their role during the migration period is small, but in the case of some reservoirs, their significance as wintering grounds is important for some species, such as Mute Swan, Tufted Duck, Goldeneye Bucephala clangula and Common Gull. Despite the importance of dam reservoirs for waterbirds in the area of the Polish Carpathians, their creation cannot be considered as a conservation measure protecting natural resources, due to the degradation caused in river ecosystems.
Keywords: Carpathians, dam reservoirs, migration, waterbirds, wintering
