Bats provide enormous ecological services including insect pest control, but their roost sites in buildings and trees are frequently disturbed or destroyed, causing welfare impacts across entire colonies.
Bats are highly vulnerable to roost disturbance as they are colonial species that concentrate in specific sites. Disturbance of maternity roosts during the nursing period causes abandonment of young, high juvenile mortality, and breeding failure. Destruction of hibernation roosts in winter when bats are torpid leads to death by starvation or cold exposure. White-nose syndrome, caused by an invasive European fungus, has devastated North American bat populations without effective treatment. Pesticide use reduces the insect prey base that bats depend on. Domestic cats kill large numbers of bats, particularly juvenile bats learning to fly. Wind turbine siting without appropriate bat assessment causes mass mortality through barotrauma.