with frequencies beyond the hearing range of birds. Mating and reproduction N. lasiopterus is understudied due to its rarity; very little is known of its mating habits, reproductive pattern, life cycle and sex ratio. N. lasiopterus, as a Nyctalus species, has an outstanding capability for migration which can possibly result in considerable seasonal changes in sex ratio. The studies in North-East Hungary indicates that the sex-ratio differs greatly depending on the location. Males were exceedingly dominant in Greece and the Czech Republic while females were dominant in NE Germany, the Moscow-region, Voronezh, and NE Hungary. This sexual segregation is due to difference in sex-specific thermoregulatory and energetic requirements. The females are dominant in warmer locations because it is optimal for fetal development and milk production. On the other hand, males are dominant in cooler locations because of lower energetic demands. These results verified that N. lasiopterus have nursing colonies located in Hungary. Ecological interactions The greater noctule bat is known to participate in a fission-fusion society. These societies vary in size, but studies show that each society has a social order and a territory in a specific group of trees that are used for roosting and breeding. The greater noctule bat has been shown to travel between several roosting sites and to participate in several societies through radio tracking studies. It has been conjectured that ranking in society dictates different roles in society, e.g. some bats are scouts, others are hunters. There has been correlation between a specific bat's social ranking and the size of that bat's potential home range; the higher the social ranking, the lower the home range. The greater noctule bat has an observed active range of 2500 km2. which is one of the largest observed ranges for any bat species. This large area of activity has several effects on the way the greater noctule bat forages and roosts. It has been noted that changes by humans to the natural environment could have had an effect on the way the greater noctule bat travels and roosts in its attempts to find suitable food sources. It has been noted that a lack of roosting sites near food sources could be the reason for the large home range that is displayed by the greater noctule bat. Differences observed between two populations of bats with drastically different habitats, Great Britain and Spain respectively, show that the greater noctule bat would