The biggest European Woodpecker selects his breeding site based on some clear indicators. Read the general information about the species here in the online bird guide.
This species is very important to other cavity breeding species and is as such recognized as a key species. This bird excavates cavities with a mean diameter of 51 centimeters. It prefers its old nest, only 4 out of 10 nests are excavated newly during the breeding season. It prefers (in a study in italy) silver fir Abies alba and larch Larix decidua as cavity trees. In Norway also spruce Picea abies and Silver fir were found to be positively associated. A predictor for a cavity tree is the diameter of the tree at breast height of the Woodpecker and the height of the tree crown. The presence of dead logs and a thick understorey were also associated with a breeding site.
Overall, the researchers conclude that the Black Woodpecker behaves like an opportunist when choosing feeding site with a marked preference for large trees with high crown height.
Research Article
Black Woodpecker Dryocopus martius habitat selection in the Italian Alps: implications for conservation in Natura 2000 network
ANDREA R. PIROVANO and GIOVANNI ZECCA
http://dx.doi.org/10.1017/S0959270913000439