Welfare of Wild Birds in Window Strike Prevention

An estimated 1-2 billion birds die annually in the US alone from glass window and building strikes, making architectural glass one of the largest human-caused sources of bird mortality globally.

Key Facts

The American Bird Conservancy estimates 599 million to nearly 1 billion bird deaths from glass strikes annually in the US alone
Glass is lethal because birds cannot perceive it as a barrier, seeing sky or plant reflections rather than solid surface
Most glass strikes occur at houses and low-rise buildings rather than skyscrapers, making household solutions highly impactful
Ultraviolet-reflecting glass patterns that birds can see but humans largely cannot are an effective and aesthetically acceptable solution
Tempera paint, film, and external screens applied to existing glass significantly reduce collision rates
The New York City FLAP initiative has recovered thousands of stunned birds from building strikes for rehabilitation

Welfare Considerations

Window strike mortality is a diffuse welfare harm occurring at enormous scale but invisible as a collective phenomenon because each death happens individually and privately. Birds that die from window strikes experience varying degrees of suffering from rapid death on immediate contact to prolonged stunned states with injury. Prevention is both effective and economically accessible: window film, external screens, and collision-deterrent glass products are widely available. This is an area where individual household action aggregates to meaningful collective welfare impact, making it one of the most cost-effective per-death-prevented welfare interventions available to the general public.

What You Can Do

Apply window collision prevention film or screens to glass windows in your home
Position bird feeders either within 0.9 metres of glass or more than 9 metres away to prevent strikes
Choose bird-safe glass for new buildings and renovations
Support local bird strike monitoring programmes that document and address high-collision buildings
Advocate for bird-safe design requirements in building codes for commercial and public buildings