Observation of a Western Barbastelle Barbastella barbastellus (Chiroptera: Vespertilionidae) in new ‘crevice’ boxes for bats

A Western Barbastelle, Barbastella barbastellus (Chiroptera: Vespertilionidae, Schreber, 1774), was observed to inhabit ‘crevice’ bat boxes very late in the year. In November 2016, in two out of three study areas, a small number of Western Barbastelle specimens, five individuals and one individual respectively, were observed inhabiting bat boxes at night temperatures below zero and with snow cover. The occurrence of this species in summer-type hiding places during winter weather conditions has not been reported previously in Poland.