Occupation of crevice-type nest-boxes by the forest-dwelling western barbastelle bat Barbastella barbastellus (Chiroptera: Vespertilionidae)

Abstract

Abstract. We studied the occupation of crevice-type roosting boxes developed especially for barbastelle bats Barbastella barbastellus (Schreber, 1774). Some 290 of the boxes were installed (in groups of five) in six study areas located in Poland in forests of different tree species composition. Colonization of boxes took place in the first summer season after installation. Two years after installation, a high rate of occupancy was recorded (up to 100 % groups of boxes, depending on the area). The total number of bats involved was 478, 72 % of which was the target species. Occupancy rates were highest in oak stands and lowest in those dominated by Scots pine. In all but one of the study areas, barbastelles founded colonies (and in part at least breeding colonies) in the boxes of this type. The overall ratio of the number of barbastelle colonies to the observation of individuals/small groups is 32.4 % to 67.6 %, respectively. The use of such boxes thus provides the active protection of the bat in question, and the effective study of its populations.