Abstract

The aim of this study, conducted in Central Poland, was to determine the pattern of bat occurrence in Stratmann boxes. Four species (Myotis myotis, Nyctalus noctula, Pipistrellus nathusii, Plecotus auritus) were found between 2005 and 2008. The occupancy rate increased from 9 boxes per 70 in 2005 to 34 per 70 in 2006. Regular monthly checks from March 2007 to February 2008 revealed changes in numbers of bats and in the percentage of occupied boxes. The first bats colonized boxes in March (P. auritus), and the last individuals were observed in October (N. noctula). The highest total number of individuals (n=128) and occupancy (33 per 69 boxes) were recorded in August. P. nathusii clearly dominated the bat assemblage (74.1% of records). The most marked tendency to form clusters and the biggest clusters (up to 14 individuals) were observed in July and August. From July to October two species (N. noctula, P. nathusii) probably showed mating behavior. This study demonstrated that in central Poland the Stratmann boxes have greater importance for bats in late summer and early autumn than at the beginning of the breeding season.