The ringing and every recovery of a ringed bat provide insights into the life history of the animal. Female bats, such as the brown long-eared bat(Plecotus auritus) shown here, live together in summer to raise their young in so-called nursery roosts. If many animals from a nursery roost are ringed, it is possible to obtain information about their age structure and probability of survival by monitoring the ringed animals in subsequent years. The maximum age for a European bat determined with the help of ringing is 33 years.
Bats prefer small crevices and cavities in buildings or trees as roosts, but will also occupy the entire roof truss if it is available. Bats are dependent on existing roosts, as they are unable to build a nest or dig a hole. We know from ringings and recoveries that bats are very traditional animals. Every summer, females and their daughters and granddaughters return to their ancestral roosts to raise the next generation. In the meantime, the bats sometimes stay in distant areas where they mate and hibernate. Every bat roost is protected by the Federal Nature Conservation Act.