Bird Collision with Windows and Buildings

Collisions with glass windows and building facades kill hundreds of millions of birds annually, representing one of the largest preventable sources of wildlife mortality in human settlements.

Key Facts

An estimated 100-230 million birds die annually from window collisions in the USA alone
UK estimates suggest around 100 million bird-building collisions occur each year
Most collisions involve birds chasing reflections or failing to detect transparent barriers
Simple window treatments including UV-reflecting films and external netting reduce collisions significantly
Tall glass buildings in flyways cause concentrated mortality during migration periods

Welfare Considerations

Bird-building collisions represent a massive, largely invisible welfare tragedy that occurs at an individual bird level across millions of events annually. Birds that collide with glass experience traumatic injury, including brain trauma, broken bones, and internal haemorrhage. Survivors may be stunned and vulnerable to predation or die from delayed injuries. Unlike many wildlife welfare issues, building collision mortality is highly tractable: effective prevention solutions including UV-patterned glass, external window films, netting, and bird-friendly architectural design are available and proven. The challenge is primarily one of awareness, regulation, and retrofitting existing buildings, particularly high-risk properties near green spaces and migration routes.

What You Can Do

Apply UV-reflecting window films or external netting to windows where collisions occur
Choose bird-safe glass in any new building or renovation projects
Advocate for bird-safe building design requirements in planning legislation
Rescue and report stunned or injured birds to local wildlife rescue organisations
Support campaigns for mandatory bird-safe building standards in commercial developments