Migratory Bird Welfare: Glass Building Collisions

Glass building collisions kill hundreds of millions of birds annually in North America and Europe, representing a preventable welfare harm on a massive scale.

Key Facts

Between 100 million and 1 billion birds die in window strikes in the USA annually
Reflective glass in homes and office buildings is the primary cause
Birds cannot see glass as a barrier and fly into it at full speed
Collision victims suffer traumatic brain injury, internal bleeding, and broken bones
Simple visual markers applied to glass can reduce collisions by over 50%

Welfare Considerations

Birds striking glass at speed suffer acute traumatic injury including skull fractures, internal bleeding, and spinal damage. Most die immediately or within hours of strike, but some survive with injuries that impair feeding and predator avoidance for days before death. Stunned birds on the ground are highly vulnerable to cat predation. The scale of glass collision mortality represents one of the largest human-caused bird welfare problems, yet it is largely preventable with simple building design and retrofitting measures.

What You Can Do

Apply bird-safe window markers or tape to large glass surfaces at home
Advocate for bird-safe glass requirements in new building planning regulations
Move bird feeders to within 30cm of windows to reduce impact velocity
Support American Bird Conservancy bird-safe building program
Report bird window strikes to monitor collision hotspots in your area