Factors Affecting Choice of Diurnal Roost Site by Tree-Hole Bats (Microchiroptera) in Southeastern Australia

Abstract

Tree-hole bats are adaptable enough to roost in cavities in man-made structures if these approximate natural hollows. Commonalities between occupied sites in buildings and trees were examined in an attempt to identify the factors involved in their selection by bats. Eptesicus vulturnus, Chalinolobus morio, Nyctophilus geoffroyi, N. gouldi and Mormopterus planiceps all selected roosts with entrances and cavities having one dimension not much larger than themselves. None were far from water and, although there were significant differences between species values of some roost attributes, the similarities between them are probably more important. A high degree of variability in most measured attributes suggests that none of these species is highly selective. Colony size was variable, but tended to be small and segregated by sex and species. Possible reasons for these behaviours are discussed. The implications of these findings for management and research are considered and a design for an artificial roost is presented.