This study examines the initial orientation of M iniopterus schreibersii (Kuhl, 1817) when released from their roosts and analyses the significance of rivers as landmarks in bat navigation. Two orientation tests were carried out in which the bats were released in areas familiar to them and two further tests were carried out in unfamiliar areas. In both types of areas one of the tests was performed close to a river and the other away from a river. Initial orientation capability of M . schreibersii was verified in all tests except in unfamiliar area away from a river. The test performed in unfamiliar area with river showed higher mean angular deviation and lower directionality than the two tests performed in familiar areas. M ost of the bats released near a river both in a familiar area and in an unfamiliar one turned towards the watercourse. The results obtained in these two last tests proved that the bats tended to turn towards the river. There were no significant differences between the directions taken by males and females in each of the four tests. Rivers seem to be landmarks in the navigation of the species and also paths to be followed in migratory flights.Instituto Pirenaico de Ecología (C .S .I.C .), avenida M ontañana 177, Apartado 202,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.