Spatial pattern of nest-box occupancy in the Pied Flycatcher Ficedula hypoleuca in mountain birch forest

Abstract

The spatial pattern of nest-box occupancy of the Pied Flycatcher Ficedula hypoleuca was studied in a mountain birch forest in Finnish Lapland using a long-term data set (1967-1991) and spatial autocorrelation techniques (Moran's I andjoin-count statistic) . The study plot consisted of 34 25 x 25 m quadrats with a nest-box in the centre of each quadrat. The plot was heterogeneous in habitat structure and showed evidence of clumping of like forest types (productive vs . unproductive forests) . When data for all years were lumped and analysed together, no spatial autocorrelation in nesting area occupancy appeared, i .e . frequencies of pairs/quadrat were arranged at random over the study plot . Furthermore, productivity of the forest area near the nest site played only a minor role in the nest-box selection of the Pied Flycatcher . The results for the individual years indicated either a random or a regular pattern of nest distribution . The Stouffer combined test supported regularity . This result stresses the importance of intraspecific territoriality even in the far north where bird populations are relatively sparse. Regularity of spatial pattern was especially pronounced in high-density years