High-Resolution GPS Tracking of Perch-Hunting Bats, Rhinolophus nippon, during Nightly Foraging Behavior

While the echolocation behavior and specialized adaptive auditory system of the greater horseshoe bat (Rhinolophus ferrumequinum) are well documented, comprehensive insights into its wild ecology, especially its detailed nocturnal movements for foraging behavior, remain scarce. Therefore, our objective was to obtain information on the spatiotemporal features of the movements of the Japanese greater horseshoe bat (Rhinolophus nippon), a close relative of R. ferrumequinum, during foraging. Hence, we investigated the nightly flight paths of R. nippon using high-resolution GPS data loggers. Initially, hidden Markov modeling analysis classified bat flight paths into two behavioral patterns: commuting and area-restricted behavior, the latter primarily corresponding to foraging activities. Focusing on foraging behavior along their trajectory, we observed that R. nippon repeatedly foraged with brief stops lasting only a few minutes and an average distance of approximately 300 m between any two foraging sites. Notably, one individual covered a considerable distance (23.6 km) from its roost, possibly because of irregular social behavior during the mating season. Furthermore, for commuting, bats occasionally used forest roads, which were located along the middle of relatively steep slopes. In cases of echolocations with limited detection distances, echoes from the ground and adjacent tree lines offered crucial navigation cues, underscoring the significance of forest roads as nightly movement routes for echolocating bats. Overall, our findings highlight the importance and urgency of ongoing research on bat movement ecology in Japan.