A maternity colony of Vespertilio murinus in Ozora, Abashiri District, Hokkaido

Abstract

A maternity roost of bats was found in a closed elementary school in Ozora, Abashiri District, Hokkaido. After measurements of their external and cranial characteristics and the number of nipples, the bats in the colony were identified as Vespertilio murinus. In July, about 60 adult females emerged from the roost. According to the results of a capture survey, the adult female gave birth in late June and early July. In August, almost all of the members of the colony were volant young, and the adult females had already dispersed. The echolocation call of flying V. murinus had a typical frequency-modulated/quasi-constant frequency (FM/QCF) structure (mean peak frequency=26.1 kHz), although the ratio between FM and QCF components varied with the flying spaces of the recorded individuals. To our knowledge, this is the first time that a roost of V. murinus has been found in Japan, and we believe that V. murinus is a resident species in Japan.