Franchuk M. Interspecies differences in morphology, breeding ecology and postembryonic development of thrushes (Aves, Turdidae, Turdus) in Ukrainian West Polissia

The dissertation is the first complex eco-morphological study of five close species of thrushes from genus Turdus (T. pilaris, T. merula, T. iliacus, T. philomelos, T. viscivorus). For the first time, on the bases of representative materials and using methods of univariate and multivariate statistics main forms of group variability and adaptive divergence were studied in five species of Turdus genus. Also, the research covered their breeding ecology, postembryonic development, and the establishment of between-species differences on late stages of ontogenesis. Ecological segregation of five thrush species, level of their divergence and sex differences were evaluated using morphological features. Adaptive character of interspecies divergence in body proportions was revealed.It was shown that nesting period consists of three phases: early, middle and late nesting stages in the development of chicks. In the postembryonic development of chicks, the phase of intensive growth can be separated (from 1 to 7-9 day), when growth processes are dominating, and the phase of slow growth, when there are intensive growth and differentiation of plumage. Interspecies differences in thrushes start to develop in the embryonic period and form during the whole postembryonic period, reaching their final point in adults.