Wild Bird Collision Prevention at Windows

Window strikes kill an estimated 100-900 million birds annually in North America alone, making glass buildings one of the most significant human-caused bird mortality sources.

Key Facts

An estimated 30-100 million birds die from window strikes in the UK annually
Birds cannot perceive glass as a barrier - they see the reflected sky or vegetation and fly into it
Ground-floor and low-rise windows cause most casualties, not skyscrapers
UV-reflective window markers invisible to humans but visible to birds reduce strike rates significantly
Window hawk silhouettes are largely ineffective unless they cover the majority of the window surface

Welfare Considerations

Window strikes cause acute traumatic injury - many birds die immediately from internal hemorrhage and brain trauma, while survivors often suffer from concussion, internal bleeding, and impaired navigation. Injured birds that appear to recover and fly away frequently die within hours from delayed trauma. Prevention is straightforward and highly effective. UV-reflective films applied to windows, patterned glass, external screens, and close-spaced vertical or horizontal stripes all reduce strike rates by making glass visible to birds. The welfare impact of widespread adoption of simple prevention measures would be enormous given the scale of window-related bird mortality.

What You Can Do

Apply UV-reflective window markers or patterned film to bird-strike-prone windows in your home
Support building design standards requiring bird-safe glass in new constructions
Report window strike casualties to the British Trust for Ornithology citizen science program
Provide first aid to concussed birds - keep them in a dark box for an hour before release
Advocate for bird-safe glass requirements in planning regulations for commercial buildings