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The diets of Natterer's bat Myotis nattereri and the common long‐eared bat Plecotus auritus were investigated at a nursery colony of each species by analysis of droppings collected monthly from May to September. Respectively, 68% and 42% of the diets comprised items presumed to have been gleaned from foliage or other surfaces: diurnal insects, insects which rarely fly, and non‐flying arthropods. Such surfaces included the ground: centipedes were eaten by both bats, and the muscid, Scatophaga stercoraria, usually associated with cattle dung, was a common prey. Indeed, the prevalence of cattle‐farming around both of the bat roosts almost certainly contributed indirectly, in the form of S. stercoraria, to a significant part of the Diptera consumed. The chief food of M. nattereri was the larger Diptera, but Trichoptera, Hymenoptera and Arachnida were also important. Lepidoptera, Coleoptera and Hemiptera were minor prey, with Dermaptera and Chilopoda taken occasionally. Diptera, closely followed by Lepidoptera, together accounted for nearly two‐thirds of the diet of P. auritus. Also taken, in descending order of importance, were Trichoptera, Arachnida, Chilopoda, Coleoptera, Dermaptera, Hymenoptera and Hemiptera. Plecotus auritus, but not M. nattereri, was evidently able to take a few small insects such as aphids and lesser nematoceran Diptera.

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Leisler's bats Nyctalus leisleri, from two nursery colonies were radio-tracked from April to August in 2 years. They commuted directly to foraging sites up to 13.4 km away at speeds often exceeding 40 km h -1 . Except during lactation, individuals occasionally day-roosted away from the nursery in buildings or hollow trees. These were also sometimes used as night roosts, especially during rain, which also stimulated return to the nursery. On most nights the ®rst¯ight lasted the longest. During preparturition, when distances from roost to foraging site were greatest, and time spent¯ying per night (t F ) was least, there was often only one¯ight, with a second towards dawn on warmer nights, and occasionally a third. After parturition, in June, t F and the number of¯ights (N F ) increased up to weaning, corresponding to rising energy demands. But distances to foraging sites fell, rising only slightly in postlactation, presumably because insects, and thus feeding patches, were more abundant than in preparturition. N F fell to preparturition levels after lactation. Exploratory behaviour by juveniles intensi®ed with time ± distances to feeding sites, t F and the total distance¯own each night all increased; the distance¯own each night was eventually greater than any recorded for adults. Roosting away from the nursery was also more common. Before dispersal, there were extended migrations by juveniles outside the summer range of the adults. Distances moved by two dispersed juveniles exceeded 34 km. Two-thirds of the recorded foraging time was over pasture or drainage canals. Foraging over other habitats, particularly lake and conifer forest, was greatest in preparturition. Other habitats foraged included lights, estuary, stream, beach and dunes.

At one nursery roost of Leisler's bat Nyctalus leisleri, the ®rst bat often, and over half of the colony exceptionally, left before sunset. Departure was earlier during the period of lactation, when energy demands were highest. Consequently emergence data had to be standardized to allow for this before investigating possible associations with light intensity and meteorological factors. The importance of such standardization in general is emphasized. Emergence was earlier on overcast nights and was delayed with increased light intensity. The bats in a neighbouring roost, from which fewer data were obtained, also left earlier on overcast evenings, but departure was generally later than in the ®rst roost, and there was no evidence of its being earlier during lactation. These differences between the roosts may be at least partially explained by the difference in size of the exit holes. At both roosts departure was mainly as a series of outbursts, and this was more marked during the ®rst half of emergence. Rate of emergence increased with colony size. It was unusual for the ®rst bat to leave more than 30 min, or for any bat to leave over 60 min, after sunset. Heavy rain inhibited or disrupted emergence.