Maternity roosts where female bats gather to raise pups are the most welfare-critical bat habitat; disturbance or exclusion during the maternity season causes pup mortality.
Maternity roosts represent the highest-welfare-stakes bat habitat because pups are completely dependent on adults who must return reliably to nurse them. Disturbance that causes adult departure results in rapidly chilling pups that die before the roost is reoccupied. Building owners who discover roosts after planning renovation projects face welfare and legal obligations that require careful navigation. The welfare-protective approach involves surveying buildings before any renovation work, obtaining appropriate licenses for work affecting roosts, and designing in bat features that maintain or enhance roost habitat through and after renovation.