Factors affecting the density of the middle spotted woodpecker Dendrocopos medius: a macrohabitat approach

The main goals of this study were to investigate the relationships between densities of the breeding population of the middle spotted woodpecker Dendrocopos medius obtained on 19 large-scale plots, and the share of different habitats and age of forest stands. An average crude density based on an area defined arbitrarily by observers was 0.66±0.43 territories/10 ha, while the ecological density based on an area including habitats potentially used by organisms reached 1.09±0.64 territories/10 ha. Stepwise multiple regression indicated that the crude density was negatively affected by the share of coniferous forest thereby explaining 50% of variation. The ecological density was negatively correlated with the percentage of young deciduous stands (0–40 years old). This variable explained 36% of the total variation. These results suggest that on the level of macrohabitat analysis, the share of unsuitable forest stands seem to play a major role in determining the density of the middle spotted woodpecker.