Grzegorz Zawadzki, Dorota Zawadzka, Anna Sołtys, Jerzy Zawadzki
Ornis Polonica 2019, 60: 47–57
https://doi.org/10.12657/ornis.2019.1.3
Abstract: The number and distribution of the Mute Swan Cygnus olor in the Special Protection Area PLB200002 Augustów Forest (NE Poland) were studied on 64 lakes and 14 watercourses. In 2016–2018, 2–3 surveys were carried out on all the lakes of the area, from boat on the main rivers and by foot along smaller watercourses. Breeding Mute Swans were recorded on 76.6% of lakes, and only on 29% of surveyed watercourses. In total, 131–162 pairs of the Mute Swan were breeding annually in the studied area. The density of the breeding population was estimated at 9.7–12.1 pairs/100 km2 of the total area. Most of the population nested on lakes (90–110 pairs), and fewer on rivers (39–47 pairs). Single pairs occupied different habitats. The Czarna Hańcza River and Lake Wigry were the most important breeding sites of the studied species, with >20 nesting pairs recorded annually. The present data indicate that 2.1% of the national population of the Mute Swan breeds in the Augustów Forest, and thus the species should be considered as an object of protection in the SPA the Augustów Forest. Each year 170–250 non-breeding birds were observed within the study area. During the autumn migration swans were recorded most frequently on Lake Wigry; their numbers there were estimated at 150–200 individuals, and at 220–300 individuals in the whole SPA. Every year some individuals tried to spend winter on Lake Wigry and the Czarna Hańcza River.
Keywords: Cygnus olor, density, Lake Wigry, Mute Swan, numbers, the Augustów Forest
