Billions of birds migrate each year, facing a gauntlet of human-made hazards including glass buildings, communications towers, and habitat loss along flyways.
Migratory bird welfare challenges are distributed across thousands of kilometres and involve hazards that individually seem minor but collectively cause billions of deaths annually. Window strikes cause concussive injury — many birds die immediately while others suffer brain injury and die slowly over hours. Tower entanglement causes exhaustion, wing injury, and death. Cat predation, while often rapid, involves the stress of pursuit and capture. The cumulative welfare burden of migration hazards falls disproportionately on already-stressed animals whose energy reserves are depleted by the journey itself. Many of these hazards are directly addressable through building standards, lighting policy, cat management, and habitat corridor protection.