Breeding microhabitat selection by great tits Parus major in a deciduous primeval forest (Białowieża National Park, Poland)

Capsule: Great Tits breeding in natural cavities in a primeval forest occupied microhabitats containing larger trees, but small differences between ‘breeding’ and ‘non-breeding’ locations indicated the minor importance of microhabitat selection in nest-placement decisions. Aims: We tested whether Great Tits breeding in primeval conditions used vegetation composition to choose breeding patches. Methods: Great Tit territories and nest-trees were mapped in two study areas in deciduous, old-growth forest. We compared tree species composition, tree girth and condition between ‘breeding’ and ‘non-breeding’ plots. Results: Great Tit territories were tightly packed, filling most of the available area. Vegetation composition in ‘breeding’ and ‘non-breeding’ plots differed only for trees that could potentially harbour Great Tit nest-cavities; ‘breeding’ plots contained larger trees. The distribution of Great Tit nests varied between years, with some ‘non-breeding’ patches in one year becoming ‘breeding’ ones in another. Conclusion: It seems unlikely that nest-placement decisions by Great Tits are constrained by the microhabitat quality under primeval conditions.