Faecal pellets were collected under one maternity colony of each of E. serotinus (E.s.) and E. nilssonii (E.n.). The distance between the colonies was 83 km. In total, 325 pellets (13 samples) of E.s. and 150 pellets (6 samples) of E.n. were analysed. Nematoceran Diptera, mainly Chironomidae, were the most frequent food items in both species. Coleoptera, Lepidoptera, Heteroptera (Corixidae, Lygaeidae) and Hym enoptera (Formicoidea, Ichneumonidae) were common in E.s., Lepidoptera, Heteroptera (Miridae), Aphidomorpha, Psyllomorpha and brachyceran Diptera were common in E.n. If the samples of the two species are adjusted to the same time (16 June – 15 August), the prevalence of Coleoptera and Hymenoptera in E.s. and Heteroptera and Lepidoptera in E.n. are highly significant (p E.s. is less significant (p jk) fluctuated between 6 % and 80 % with an average of 69 %. Prey diversity (H’), evenness (J’), measure of niche breadth (B) and the representation of four major insect groups varied seasonally and in the two species independently of each other. Both species prefer aerial hawking and hunt for swarming insects if available. Comparison with data of other authors revealed regional differences in foraging and diet within each of the species studied.
The aim of our study was to assess the seasonal and overnight changes in the flight activity and habitat use of four bat species under the conditions of a sub-mountain town by a detector monitoring. The urban habitats visited from May untill October 1998 – 2000 were divided into three categories: gardens (illuminated or non-illuminated gardens and larger groups of trees), urban habitat (old and new buildings in suburbs and downtown), and water (streams and ponds). Only for Myotis daubentonii was a statistically significant increase in flight activity recorded between the lactation and post-lactation periods. The highest activity of M. daubentonii was recorded in the vicinity of water bodies. The activities of Pipistrellus pipistrellus and Nyctalus noctula were similar in relation to the habitats. Only in Eptesicus serotinus was the activity recorded per habitat type not significantly different. The changes of activity of P. pipistrellus had a bimodal character with the first peak in the 5th and the 6th ten-minutes and the second in the 12th ten-minutes. In N. noctula, activity was characterized by commuting over the urban habitats during the first 0.5 h. Relatively high activity was recorded in E. serotinus during the first 0.5 h in gardens.