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.