Wild Bird Window Strike Prevention and Welfare

Window strikes kill an estimated one billion birds annually in North America alone. Simple, proven interventions significantly reduce this preventable source of wild bird mortality and suffering.

Key Facts

An estimated 600 million to 1 billion birds die from window collisions annually in the United States alone
Glass is the second largest human-caused source of bird mortality after cats in North America
Birds cannot perceive glass as a barrier and fly at full speed into reflective or transparent surfaces
Strikes that do not immediately kill often cause traumatic brain injury and delayed death
Corner windows, angled glass, and large panes present the highest collision risk
UV-reflective glass patterns visible to birds but not humans are highly effective at reducing strikes
Simple DIY solutions including decals, external screens, and tape patterns reduce strikes by over 70%

Welfare Considerations

Window strike survivors that do not die immediately experience traumatic brain injury, internal bleeding, and disorientation. Birds found stunned after strikes often die within hours from delayed haemorrhage or predation while incapacitated. Preventive action at the building design stage is far more effective than rehabilitation. Research shows that most window collisions are entirely preventable through well-evidenced, affordable modifications. The scale of mortality means even modest per-building reductions produce significant welfare and conservation gains.

What You Can Do

Apply collision-prevention patterns to high-risk windows — coverage of at least 25% of glass surface is effective
Use external screens or netting as a highly effective but invisible prevention measure
When building or renovating, specify fritted glass or bird-safe glazing products
Support American Bird Conservancy's Bird-Smart Glass certification programme
Advocate for mandatory bird-safe glass requirements in new commercial building codes