Pipistrellus nathusii 7, Ruige dwergvleermuis, Saxifraga-Rudmer Zwerver.jpgNathusius pipistrelle bat on bark of tree Nathusius' pipistrelle (Pipistrellus nathusii) resting on tree. This is a small migratory bat in the pipstrelle genus. Large flocks travel from northern to southern Europe every spring and autumn.