Recapture of a banded Bechstein's bat (Chiroptera, Vespertilionidae) after 16 years: An example of high swarming site fidelity

In late summer and autumn, many species of hibernating temperate bats that form mixed-sex groups visit swarming sites (typically caves or mines). Swarming behaviour is mostly prevalent among bats of the genus Myotis and has a crucial role in maintaining gene flow among colonies that are socially isolated and thus demographically independent. This note reports on a recapture record of a Bechstein's bat (Myotis bechsteinii) in proximity of the “Grotta Marelli” cave, in the Campo dei Fiori Regional Park (Varese, N Italy). We recaptured a male individual twice, i.e. 3 and 16 years after the first observation, which took place at the same site in 1999. Our observation supports previous studies suggesting that Myotis bats are faithful to swarming sites and documents a further record of loyalty to a swarming site, close to the maximum known lifespan (21 years) for M. bechsteinii.