Lack of specialist nidicoles as a characteristic of mite assemblages inhabiting nests of the ground-nesting wood warbler, Phylloscopus sibilatrix (Aves: Passeriformes)

Bird and mammal nests provide microhabitats that support a range of other species, including invertebrates. However, the variation between communities of nest-dwelling invertebrates in different nests is poorly understood. The major aim of this study was to analyze the assemblage structure of mites from the suborder Uropodina (Acari: Mesostigmata) and from superfamily Crotonioidea (Acari: Oribatida) inhabiting nests of the wood warbler, Phylloscopus sibilatrix (Aves: Passeriformes), located on a forest floor in Białowieża Forest, in eastern Poland. We also assessed the correlation between the nest material used by the birds with the assemblage structure of Uropodina mites, and compared the results with published studies of the nests of other birds and a mammal (common mole, Talpa europaea), and also with communities of mites inhabiting the soil. The field research was conducted in the strict nature reserve of the Białowieża National Park, a near-primeval European temperate forest. In 2019, immediately after the breeding period, 69 wood warbler nests and 439 soil samples were collected. Analyses revealed assemblages of Uropodina mites inhabiting the nests that consisted of 14 species, mostly common soil species. Only five species of oribatid mites from superfamily Crotonioidea were present in the nest material. Analyzed nests had a high percentage of tree leaves and grass blades, whereas moss was the least frequent component of the nest material. The Uropodina mites were more abundant in the nests that had greater amounts of grass blades, but similar relationships were insignificant for the nests with varying amounts of tree leaves or moss. The assemblages of Uropodina mites inhabiting wood warbler nests were very similar to those found in soil and nests of the common mole, but they lacked typical nest-dwelling species of Uropodina (i.e., specialized nidicoles).

The effect of urbanization on population densities of forest passerine species in a Central European city

Typical, but less common, passerine forest species were selected for this study, such as Lullula arborea, Anthus trivialis, Troglodytes troglodytes, Prunella modularis, Turdus philomelos, Turdus viscivorus, Phylloscopus sibilatrix, Regulus regulus, Regulus ignicapillus, Muscicapa striata, Ficedula albicollis, Ficedula hypoleuca, Parus cristatus, Parus palustris, Parus ater, Certhia familiaris, Certhia brachydactyla, Oriolus oriolus, Garrulus glandarius, and Corvus corax. M. striata and T. philomelos were the most numerous among the 20 investigated species, the former one nested in a density of 6.7 pairs per 100 ha of wooded area, while the later one at 5.1 pairs per 100 ha. Density of most other species was below 3 pairs per 100 ha of wooded area. A. trivialis, P. cristatus and P. modularis were unexpectedly rare (< 1 pair per 100 ha). Otherwise, relatively numerous were T. troglodytes (1.8 p./100 ha), R. regulus (1.8 p./100 ha) and P. palustris (1.4 p./100 ha). P. cristatus, L. arborea, and T. viscivorus were the rarest species investigated (below 0.1 p./100 ha). Several bird species nested in wooded areas only in the outer zone of the city. This group included A. trivialis, R. regulus, P. ater, and C. corax. Population density of T. troglodytes, T. philomelos and O. oriolus were significantly higher in outer than in inner zone, while the reverse was true in the case of M. striata and F. hypoleuca.