Influence of landscape features on the location of grey heron Ardea cinerea colonies in Poland

We analysed hydrographic and habitat factors influencing the location of 207 colonies of the grey heron Ardea cinerea in Poland. We compared areas of particular habitats in three buffers around colonies (0-1, 0-10, 0-20 km) among eight regions differing in their proportions of studied habitats. We found the highest inter-region dissimilarities in areas covered by water bodies (all scales) and pastures (0-1 km). We recognized some indicator habitats characteristic of the majority (water bodies, pastures) or of some (seacoast, inland marshes, urbanized zone) regions. The habitat selectivity index showed that grey herons in buffer 0-1 km preferred pastures and water bodies in seven regions and rivers in one subprovince. In buffer 0-10 km, forests and urban zones were preferred in seven and five subprovinces, respectively. Our study revealed that both aquatic and non-aquatic habitats are important for the distribution of the grey heron colonies in Poland.