Michał Jantarski
Ornis Polonica 2019, 60: 16–39
https://doi.org/10.12657/ornis.2019.1.1
Abstract: Duck counts were performed in mid-May in 2016–2018 at carp fish-ponds in Poland. The area of 26 815 ha was surveyed (33% of the whole area of carp fish-ponds in Poland). A total of 35 426 individuals representing 17 species were found. The most abundant species were: the Mallard Anas platyrhynchos, Tufted Duck Aythya fuligula, Common Pochard A. ferina and Gadwall Mareca strepera, making up 97% of all ducks. A total of 4 754 female Tufted Ducks were recorded (the density of 1.8 females/10 ha of a pond area). Densities of Tufted Ducks were 3.3 times higher in southern Poland and near Kielce than in eastern and western Poland. In total 2 877 Common Pochards were counted (density of 1.1 females/10 ha). The maximum density was found near Kielce (2.7 females/10 ha), and it was 3–4 higher than in the east and west of Poland. A total of 865 female Gadwalls were recorded (density of 0.3 females/10 ha), and their densities were similar across the country. The exception was the area near Kielce, where the densities of the species were 2.5–3 times higher than in other surveyed sites. Sex ratio (proportion of males to females) in the Tufted Duck (1.21) was almost identical in all surveyed sites, while in the Common Pochard (2.55) varied considerably among the regions. In good breeding areas near Kielce the ratio was 1.61, whereas in western Poland, where the population of the species is declining, the sex ratio was estimated at 3.53. Among female diving ducks the Tufted Duck and Common Pochard were the dominants (61% and 37%, respectively), while the share of Red-crested Pochard Netta rufina and Ferruginous Duck A. nyroca was below 1%. The presence of numerous and large breeding populations in Kielce region and southern Poland is probably related to the absence of main predators of the species there (which are common in other areas of Poland): American mink Neovison vison and White-tailed Eagle Haliaeetus albicilla. Results of this survey can be referred to in future monitoring programmes of breeding ducks at fish-ponds in Poland.
Keywords: Common Pochard, diving ducks, fish ponds, Gadwall, monitoring of breeding ducks, sex ratio, Tufted Duck
