BIOMETRY, HABITAT DISTRIBUTION AND BREEDING SUCCESS IN THE PIED FLYCATCHER FICEDULA-HYPOLEUCA

Pied flycatcher, F. hypoleuca Pall., populations in deciduous and coniferous habitats around Uppsala, central Sweden, were compared. In deciduous as compared to coniferous habitat, males, but not females, were larger, territories were occupied and egg laying started 1 wk earlier, and final breeding success was higher. The size-related assortment of individuals upon the 2 habitats was interpreted as the outcome of competitive interactions. This finding and the lower reproductive success in the less preferred habitat are in accordance with Fretwell''s ideal despotic distribution model.