Maternity roosts where female bats gather to give birth and raise pups are particularly sensitive to disturbance and require careful protection during the critical breeding season.
Maternity roost disturbance causes severe welfare harm through pup mortality from hypothermia and maternal abandonment. Pups dropped by startled mothers on hard floors below the roost die within hours from cold. Even non-lethal disturbance that causes temporary roost abandonment imposes energetic costs on nursing females at a time of maximum physiological demand. The legal protection of bat roosts reflects recognition of this welfare and conservation risk. However, welfare harm from unlawful disturbance continues, particularly where bat surveys are not commissioned before building work on older properties.