Birds

Migratory Bird Window Strike Prevention

Up to one billion birds die annually in the United States alone from collisions with glass windows and buildings.

Key Facts

Birds cannot perceive glass as a barrier — they see only reflected sky and vegetation
Window strikes are the second-largest human-caused bird mortality factor in North America
Even non-fatal strikes cause concussions and internal injuries
Glass at 45-degree angles reduces strikes by making sky reflections less likely
UV-patterned glass visible to birds but not humans is highly effective

Welfare Considerations

Birds that collide with windows often die immediately or succumb to internal injuries hours later. Survivors may appear stunned and recover, but research shows many have lasting cognitive impacts from concussive injury. The suffering is brief but the scale is enormous: billions of individual animals experience painful, disorienting deaths. Prevention is both cheap and highly effective, making this one of the most tractable animal welfare problems.

What You Can Do

Apply UV-reflective window film or bird-safe decals to your windows
Plant native vegetation away from windows to reduce reflection confusion
Move bird feeders to within 3 feet of windows (too close to build fatal speed)
Advocate for bird-safe building standards in local construction codes
Support American Bird Conservancy's Glass Collisions Program