Wind turbines kill large numbers of bats globally through both direct blade strikes and barotrauma from pressure changes near moving blades. Migratory bat species are particularly vulnerable, and turbine siting in flyways creates significant welfare impacts.
Barotrauma causes internal haemorrhage and lung damage that kills bats rapidly but not instantly. Blade strikes cause direct traumatic injury. The combination of mortality during migration removes individuals from populations that are already declining due to habitat loss. Curtailment strategies that shut turbines during the specific wind conditions and seasons when bats are most active are highly effective and represent a achievable welfare improvement.