Bats and their roosts are legally protected in many countries, but accidental disturbance during building work remains a major welfare threat.
Bats disturbed in summer maternity roosts suffer acutely: pups may be separated from mothers, torpor cycles interrupted, and colony cohesion destroyed. In winter, roost disturbance during hibernation forces bats to burn fatal energy reserves. Beyond direct harm, roost destruction removes habitat needed for successful reproduction over decades. Early ecological surveys prevent most accidental harm.