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Habitat preferences of the Collared Flycatcher Ficedula albicollis (Temm.) in mountains of continental Croatia

Habitat selection of Collared Flycatcher, Ficedula albicollis (Temm.) was studied at three mountains of Continental Croatia covered with oak-hornbeam, beech and coniferous forests. Standard point count technique was used (n = 163). Collared Flycatcher territories were found at 59 points, 17 of them identified as the best territories, with two or more pairs present. Habitat at each counting point was described by the circular plot method. Each counting point was further characterized by the forest type. Differences between the proportions of available and used forest types were tested with χ 2 goodness-of-fit test. Standardized selection index (B) and 95% confidence limits with Bonferroni correction were calculated. PCA was used to identify the principal sources of variation in the habitat structure. In our study, both forest types and structural characteristics of habitat had effect on the habitat choice of the Collared Flycatcher. The Collared Flycatcher preferred oak and beech forests and strictly avoided pure coniferous stands. The best territories where mostly situated in the pure beech and mixed beech forests. PCA on habitat characteristics produced five components which accounted for 84.3% of the variation in the habitat structure. PC1 and PC3 indicated the presence of coniferous trees while PC2 and PC4 indicated the forest age. The PCA revealed significant relationship between Collared Flycatcher presence and several structural characteristics of habitat: total tree density, densities of small and large trees, shrub density and average tree basal area. The best territories were situated in the forest patches with low number of large trees. Tree density is an important factor for habitat selection in younger forests, but in stands older than 100 years, other factors play more important role in the habitat selection. The Collared Flycatcher avoided forests with dense shrub layer.

Collared Flycatcher; Ficedula albicollis; forest type; habitat characteristics

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