Studies concerning bat autumn swarming behavior suggest that the main purpose of this phenomenon is mating. However, the process of fat accumulation is crucial for surviving winter, and it seems to be in clear conflict with a need to strive for the opportunity to mate prior to hibernation. Investment in one activity limits the other one creating a trade-off between them. The aim of our study was to describe the activity pattern of each sex-age group (adult males, adult females, subadults) of the Natterer's bat during swarming period and to investigate the fat accumulation process of adult males in the context of their reproductive strategy. Bats were captured by mist nets at the swarming site fortnightly from the early August until the late November. The age, sex, reproductive status, and body condition index (mass to forearm ratio, BCI) were recorded. The activity peak of both sexes, adults, and subadults was observed in the late September. That time in season, BCI of adult males was the lowest, and there was no correlation between the hour of an adult male capture and its BCI value within one night (r s = 0.23; p = 0.157). Such correlation was observed later in the season (early October: r s = 0.44; p = 0.020; late October: r s = 0.48; p = 0.002). A negative correlation between adult males' BCI and proportion of adult females was found (r = 0.44; p = 0.000). We conclude that the activity peak of females is likely to be responsible for the effort of the mating behavior of the males, which is reflected by their low condition index. We suggest that the gleaning foraging strategy of Natterer's bat allows the males to postpone their fat accumulation until just before hibernation.

Municipal greenery can mitigate the negative impact of urbanization on biodiversity, including bats, by providing a migration corridor, food base and roosts. Our study aimed to evaluate the species composition and diversity, test the differences in activity between seasons, and identify the atmospheric conditions influencing the bats’ activity in the Planty Park (Cracow). Fieldworks were conducted in 2016 and 2017. We recorded 10 species, two new for this part of Poland: the Kuhl’s pipistrelle (Pipistrellus kuhlii) and the Savi’s pipistrelle (Hypsugo savii). Taxa were divided into three ecological guilds. Myotis group’s activity was insufficient to perform statistical analyses. The activity of Nyctalus, Eptesicus and Vespertilio group peaked in late summer. A similar insignificant trend was observed for Pipistrellus and Hypsugo. Temperature enhanced the activity of Nyctalus, Eptesicus and Vespertilio group in spring and early summer, while cloud cover suppressed their activity in autumn. Temperature also enhanced Pipistrellus and Hypsugo group activity in spring and autumn, but it suppressed their summer activity. Our study is one of the first to investigate temperate urban bats’ phenology and may serve as a preface for further research to introduce detailed urban landscape planning recommendations.

Because of thoughtless decisions or unintentional introduction, alien species disturb native ecosystems. red oak (Quercus rubra), among other alien woody plants, is still used to rehabilitate degraded land because of its better resistance to pollution and faster growth, as compared to native tree species. Soil mites, especially oribatida, are good bioindicators of ecosystem disturbance, so the main goal of this study was to explore the influence of invasive and native oaks on mite communities. forest stands dominated by 40-year-old Q. rubra or 35-year-old Q. robur were compared. over 2300 soil mites were extracted from 20 soil and 20 litter samples. mite densities in the communities were higher in red oak litter, which is probably a result of the thicker layer of shed leaves. changes in species composition of oribatid communities were observed in litter, in contrast to a lack of differences in soil. These observations are consistent with other researches on invasive woody plants. we expect that over time these changes will also be noticeable in the soil and will increase in litter.

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The northern range of R. ferrumequinum reaches the southern boundary of Poland. Evidence for this species north of this border is growing. Until now, all records were derived only from the winter period. The adult female captured in May suggests that the area of Southern Poland can be used by this species outside the hibernation period.