PDFDOI: https://doi.org/10.2478/vzoo-2018-0027
A Great Grey Owl population on the territory of Polisskiy Nature Reserve (Olevsk and Ovruch District, Zhytomyr Region, Ukraine) was investigated in 2006–2008, 2013–2016. The main breeding locations were mesotrophic mires, where the lack of Birds of Prey nests made owls to breed on artifi cial constructions. Reproductive indexes of mean clutch size were similar to such indexes achieved in 1985–1996, and indexes of mean number of fl edglings on active nest and breeding success decreased reliably.