Common pipistrelles are the UK most common bat, but roost disturbance during building renovation is a significant welfare and legal concern. All bat species and roosts are legally protected, and renovation without a bat survey and licence can cause mass mortality.
Pipistrelle pups in maternity roosts are entirely dependent on their mothers and cannot survive if the roost is disturbed and females abandon. Renovation of roost buildings during the maternity season causes death of dependent pups through chilling and starvation. Adults displaced from roosts in cold weather face energetic stress. The legal protection of roosts reflects the welfare significance of roost disturbance.