On the population ecology of the common shrew (Sorex caecutiens Laxm.) in the European part of the range. Message III. Reproduction, demographic structure of the population, molting, population dynamics

Based on long-term stationary and expeditionary studies in the taiga North-West of Russia (1958-2018), the population and ecological features of reproduction, demographic structure and population dynamics of the common shrew, including those associated with its habitat in the border European part of the range, are analyzed. It has been established that under these conditions the species is characterized by a longer reproductive period lasting from the second half of April to mid-September, characterized by the participation in reproduction mainly of only adult animals that have overwintered. The total number of broods per season is two, which also corresponds to two fairly clear peaks of the settlement of underyearlings, which occur at the end of June - the beginning of July and the beginning of August. Embryos in one female are from 5 to 11, on average (n = 21) 7.7. This is somewhat higher than that of other species of our shrews and higher than that of the same species in other parts of its range. The ecological structure of the population is characterized by a rapid increase in the proportion of underyearlings, which already in September is more than 72 %. The age composition of the population also changes over the years, correlating with the intensity of reproduction and the total population. the sex ratio depends on the age, season of the year and the state of the population. The number varies markedly over the years. but without any clear periodicity and, on the whole, not synchronously with that of the background species, the common shrew. Nevertheless, in more than 60 years of observations, only four and, moreover, very fuzzy periods of rise appear under the influence of a rather complex combination of a number of exogenous and endogenous factors.