Przemysław Wylegała, Paweł Czechowski, Andrzej Batycki, Sławomir Rubacha, Michał Barcz, Mateusz Gutowski, Damian Ostrowski, Michał Przystański, Alicja Dubicka-Czechowska, Arkadiusz Sikora
Ornis Polonica 2025, 66: 1-15
https://doi.org/10.12657/ornis.2025.1.1
Abstract: In July 2024, a breeding survey of the White Stork Ciconia ciconia was carried out in an area of 1,742 km2 of the Lower Warta and Noteć River valley. The study area was designated based on a grid of 1 × 1 km squares and divided into 5 sections: Lower Warta River valley (DDW), Lower Noteć River valley (DDN), Noteć River valley from Drezdenko to Wieleń (DNDW), Nadnoteckie Łęgi (NŁ) and Middle Noteć River valley (DŚN). 754 nests were recorded, including 619 nests inhabited by pairs. The average density for the entire area was 35.5 pairs/100 km2. The highest density was recorded in sections DDN and NŁ (49.3 and 54.0 pairs/100 km2), and the lowest in section DŚN (17.6 pairs/100 km2). Inhabited nests were found on 431 1 × 1 km plots (24.7% of all squares), where 1 to 8 pairs were recorded. Nests with 3 and 2 fledglings dominated (43.7 and 32.3% of nests with young). The lowest proportion of nests with four fledglings (7.4%) was shown in section NŁ with the highest density, and the highest (21%) in section DŚN with the lowest population density. Four clusters of nesting pairs ranging from 6 to 10 pairs were found. The average brood size was 2.39 young per pair and 2.68 young per pair with successful brood. Occupied nests were most often located on poles (92.9%), mainly power poles with platforms (74.0%). Reproduction rates of stork pairs on power poles with platforms were higher than nests on poles without platforms. The species reached its highest abundance in areas with a mosaic of habitats (sections DDW and DDN) and in areas with a high proportion of pastures (section NŁ). Over the past several years, there has been a clear increase in the White Stork population in the lower Warta River valley and stability or a slight increase in the Noteć River valley. The study area is the most important refuge of the species in western Poland and one of the key ones on a national scale, concentrating 1.2% of the national population.
