EFFECTS OF HABITAT FRAGMENTATION ON FORAGING BEHAVIOR OF TITS AND RELATED SPECIES - DOES NICHE SPACE VARY IN RELATION TO SIZE AND DEGREE OFISOLATION OF FOREST FRAGMENTS

We studied the winter foraging niches of tits and related species in d eciduous forest fragments varying in size between 1 and 30 ha (plus on e forest of 200 ha) in order to investigate the influence of forest fr agmentation on foraging niches. Very few correlations between niche st ructure (foraging niche, width and overlap) and forest size or isolati on turned out to be significant. This implies that either the species that disappear in small fragments are those that suffer most from comp etition (making the effect unmeasurable), or that competition is relat ively unimportant for niche structure. In any case we find no evidence that foraging niches are strongly affected by the changes (in habitat and/or community structure) associated with fragmentation.