Breeding bird assemblage of a fir-oak natural forest in Ponická dúbrava – the oldest Slovak nature reserve

Abstract

The bird assemblage of the Ponická dúbrava National Nature Reserve (13.3 ha), preserving a mixed nature
forest composed mainly of fir, oak, spruce and beech was studied using a modified mapping method during
the breeding period in 2015. The site is rather unique, containing elements of both lowland and mountain
forests. The aims of the study were to determine the structure of the bird assemblage, compare it with other
bird assemblages from oak-beech and mixed natural forests, and define the most important habitat indicator
species. Altogether, 37 breeding bird species were recorded and the estimated rarefaction species number per
10 ha was 30.9. Total bird density reached 63.0 pairs/10 ha. Five species were found to be dominant (>5%
of the total density): Fringilla coelebs, Erithacus rubecula, Periparus ater, Regulus regulus and Ficedula
albicollis, representing 42.6% of the total density. Comparing with other eight bird assemblages from natural
forests using a cluster analysis, the assemblage from the Ponická dúbrava clearly fits into those from mixed
beech-fir-spruce forests. Factor analysis revealed six species separating the assemblage from oak-beech
stands: Regulus regulus, Poecile montanus, Periparus ater, Pyrrhula pyrrhula, Prunella modularis and
Turdus viscivorus. Based on our data, the reserve represents a valuable rare natural habitat of very high bird
species diversity.