Oribatid Mites (Oribatida) Associated with Nests of Open-Nesting Birds of the Genus Thrush (Turdus) in the Taiga Forests of the European North-East of Russia

For the first time, studies have been conducted aiming at the diversity of the oribatid mites (Oribatida) that inhabit the nests of open-nesting birds of the genus thrushes (Turdus), particularly fieldfare (T. pilaris Linnaeus, 1758) and redwing (T. iliacus Linnaeus, 1766), in the taiga forests of the European north-east. Long-term observations were carried out in the green belt of the city of Syktyvkar (N 61°40′ E 50°50′) in 2021–2025. Among 168 studied thrush nests (fieldfare—138, redwing—30), 1982 specimens of oribatid mites of 35 species from 33 genera and 26 families were found. The nests of thrushes contain a mixed fauna of oribatid mites, including the following: (a) Soil species that obviously enter the nest with building materials collected by birds from the soil surface. These are epigeic species such as Eupelops plicatus, Neoribates aurantiacus, and Chamobates pusillus; hemi-edaphic species such as Heminothrus peltifer; and euedaphic species such as Oppiella nova and Quadroppia quadricarinata. (b) Tree-dwelling species that have been recorded as inhabiting epiphytic lichens in the European north-east, such as Ameronothrus oblongus, Ceratoppia quadridentata, Oribatula propinqua, Trichoribates berlesei, and Diapterobates oblongus. (c) Eurybiont species such as Tectocepheus velatus, Scheloribates laevigatus, and Oribatula tibialis. An increase in the number and diversity of oribatid mites was noted in nests collected after the end of the nesting period and the flight of chicks compared to nests collected in the spring (overwintered nests).