Sławomir Mielczarek, Aleksander Winiecki
Ornis Polonica 2017, 58: 244–273
https://doi.org/10.12657/ornis.2017.4.1
Abstract: This paper describes non-breeding avifauna recorded in the area of five lakes and two artificial water bodies, including fish-ponds near Konin (central Poland). These water bodies, connected by canals, are used for cooling coal-fired power stations. The lakes have considerably elevated temperatures, and host many foreign and expansive plant and animal species, especially fishes and bivalves. The study was carried out from autumn 2010 to spring 2011. The results have been compared with unpublished data collected in the past during three seasons, including the data gathered at the turn of the 60s and 70s of the 20th century. Both present and past bird species richness result from the low depth of the lakes, high biomass of benthic fauna, and the absence of complete ice cover even during severe winters. These conditions attract high numbers of benthophagous (Coots Fulica atra and diving ducks Aythya sp.) and ichthyophagous bird species (herons Ardea sp., cormorants Phalacrocorax carbo, grebes Podiceps sp., mergansers Mergus sp.). The most important water bodies for these species are two the shallowest and constantly heated lakes Gosławskie and Pątnowskie. A significant decrease in the Coot numbers throughout the study years may result from the population fluctuations but also a decline of the breeding populations. The important increase in the numbers of fish-eating species, especially the Great Cormorant, is related to the species expansion, and locally – to high food abundance. Large flocks of migrating and wintering gulls and geese have been formed as a result of global changes, the presence of advantageous roosting site (warm, unfrozen waters) and close proximity to good foraging sites (garbage dumps, fields and meadows).
Keywords: abundance changes, heated up lakes, waterbirds
