Doorzonwoning slecht voor de Grote Bonte Specht Dendrocopos major

In 1993, Great Spotted Woodpeckers were studied in the forestry of Odoorn (1730 ha)(Table I, Fig. 1). Territories were mapped and once a nest was found, its content was examined with the aid of a mirror and a maglight. Eggs were counted and the age of nestlings was estimated. Some parameters of the nest site were quantified (Figs. 1-4). In the study area 160 territories were mapped in which 46 nests were found (fig. 1). Great Spotted Woodpeckers preferred nesting in broad-leaved trees. Given their scarcity, a preference for excavating holes in dead trees was found (Table 2). Laying of the first egg in 43 nests varied from April 24 to May 15 (mean May 2, SD=5.2). One repeat-clutch was started on May 25; in this case, the first clutch was started on May 6. Clutch size in 22 nests ranged from four to seven eggs (mean 5,7, SD=0.89). Clutch size declined in the course of the breeding season (Fig. 6). Breeding success was high. The chance that a cluch produced hatchlings was 82%. Once they had young, all pairs succeeded in fledging them. A total of three nests failed, two of which were depredated. Both nests were excavated in slender (girth at nest height 50 cm), dead trees. Predators had forced a hole in the side of the nest, right through the wall.