Włodzimierz Meissner, Tomasz Chodkiewicz, Łukasz Wardecki, Paulina Siejka, Jacek Antczak, Wiesław Bagiński, Jacek Betleja, Dawid Cząstkiewicz, Paweł Czechowski, Maciej Filipiuk, Andrzej Górski, Paweł Grochowski, Grzegorz Grygoruk, Robert Hybsz, Zbigniew Kajzer, Adam Kaliński, Marcin Łukaszewicz, Dominik Marchowski, Patryk Rowiński, Włodzimierz Szczepaniak, Kazimierz Walasz
Ornis Polonica 2022, 63: 215–244
https://doi.org/10.12657/ornis.2022.3.3
Abstract: In January of 2020, counts of waterbirds wintering in Poland were conducted encompassing 2,390 waterbodies of different kind. In total, there were 1,289,455 individuals observed, including 1,180,513 birds of identified species that were present on different sites, 39,634 individuals in flight and 69,308 birds of unidentified species. The most numerous species was Mallard, accounting for 41.9% of all observed birds, and its abundance exceeded 500,000 indiv. The total number of individuals of every consecutive species: Bean Goose Anser fabalis sensu lato, Tufted Duck Aythya fuligula, Coot Fulica atra, Greylag Goose A. anser, Common Goldeneye Bucephala clangula, Herring Gull Larus argentatus sensu lato and Cormorant Phalacrocorax carbo exceeded 40,000 indiv., and percentage of each species did not exceed 3%. These most numerous species accounted in total for 78.5% of all sighted birds. Bird concentrations of more than 20,000 indiv. were recorded on 8 sites gathering in total 21% of birds recorded during the counting. Number of birds observed in Szczecin Lagoon with the Świna Delta, the Outer Puck Bay and in Włocławek Reservoir exceeded 40,000 birds. The described winter season was extremely mild which certainly affected the obtained results since the abundance of birds wintering in Poland to large extent is dependant on the harshness of winter. Lower winter temperatures in eastern Poland usually result in lower number of wintering waterbirds compared to the western part of the country. These variations in many species were also seen in January of 2020, when temperatures were exceptionally high. However, in comparison to harsh winters, higher numbers than usual were recorded in eastern Poland of Teals Anas crecca, Mallards, Mute Swans Cygnus olor, Greylag Geese and Grey Herons Ardea cinerea. The very mild winter also caused the occurrence of species rarely wintering in Poland such as Spotted Redshank Tringa erythropus, Common Sandpiper Actitis hypoleucos and Sandwich Tern Thalasseus sandvicensis. The weather conditions were also favourable for numerous occurrence of such species as Lapwing Vanellus vanellus, Golden Plover Pluvialis apricaria, Curlew Numenius arquata, Common Snipe Gallinago gallinago, Green Sandpiper T. ochropus, Water Rail Rallus aquaticus and Bewick’s Swan C. columbianus.
Keywords: abundance of population, water bodies, wintering
