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Abstract.
The food composition of noctule bats (Nyctalus noctula) was investigated using droppings analyses methods (29 samples/322 pellets) over two winters (2001/2002 and 2002/2003) in ten urban and rural localities in Central Europe (Slovakia, Czech Republic). Two orders of arachnids (Araneida, Acarina) and nine orders of insects (Homoptera, Heteroptera, Psocoptera, Neuroptera, Coleoptera, Hymenoptera, Lepidoptera, Diptera, Siphonaptera) were identified in the droppings. The most important order in all samples was Lepidoptera (mean F = 53 %, mean V = 35 %), followed by Diptera (F = 38 %, V = 12 %), Coleoptera (F = 21 %, V = 9 %) and Araneida (F = 15 %, V = 3 %). Differences were found in the composition of the most important food components among two urban and one rural locality as well as in the portion of secondary components (hair, slime). Regarding seasonal changes in the food composition, three periods were identified in winter - the beginning (November - January), the middle (February) and the end of the season (March). Some seasonal trends could be identified in the Diptera and Coleoptera, with a decrease in frequency and volume in the middle of the winter. The most important food component (Lepidoptera) showed no seasonal trend over winter. The bats could hunt insects outside or collect them also very probably directly in the shelters.
Key words: Chiroptera, foraging ecology, winter, Europe
Introduction
The winter activity of holarctic bats at latitudes above 48° was reported in some species dwelling in caves or other underground habitats as well as in species hibernating in buildings (e.g. Ransome 1971, Avery 1985, 1986, Brigham 1987, Park et al. 1999). However, food quality was not analysed in these studies. It is clear that this activity of bats during winter time depends on a sufficient energy supply which means on the amount of available food (invertebrates) during this unfavourable time (Brigham 1987).
The common noctule bat Nyctalus noctula (Schreber, 1774) is a species that is conspicuous by flight and calling activity during winter, and also at temperatures under 0 °C (feeding buzzes can be registered using a bat-detector) (Gaisler et al. 1979, Avery 1986). It is possible to observe flying and calling activity mainly in the vicinity of prefab houses in towns of...