Przemysław Wylegała, Andrzej Batycki, Tadeusz Mizera
Ornis Polonica 2011, 52: 75–84
https://doi.org/10.12657/ornis.2011.2.0
Abstract: The study describes the number and distribution of the Grey Heron in the Wielkopolska Province, gives basic data about the habitat and colony characteristics and compares current results with the previous ones. Most of the data were collected during the 2010 regional census of heronries, but it also uses data from 2006–2009. A total of 34 colonies with 1629–1650 pairs of Grey Heron were found in 2010. The average density of the species in the Wielkopolska Province was 0.9 colony and 42 nests/1000 km². Over the last decades, Grey Heron population can be considered to be stable. The average colony consisted of 48 pairs (SD=43.8, median 37). Four colonies were mixed-species with the Cormorant Phalacrocorax carbo. The Grey Heron nested on 25–165 year-old trees. Most colonies (79.4%) were localized on trees younger than 80 years. The Grey Herons built their nests on 10 tree species, mostly on pines (76.8%), willows (6.5%) and oaks (5.9%). On average, heronries were located at a distance of 295 m (range 45–950 m) from human settlements, and 710 m (range 0–2200 m) from foraging grounds. Most colonies were located up to 500 m from the buildings (81,6%). Of 10 colonies which changed their locations in recent years, 9 moved closer to human settlements, which resulted in shrinking of the average distance from the buildings from 1060 m to 260 m. The 11 out of 40 known colonies in 2006–2010 were located in large forests (6.5–75 km²), 2 colonies – on islands at the lakes, and the remaining 25 within small woods (0.1–200 ha).
