Bird Window Collisions and Prevention

Window collisions kill an estimated 100-900 million birds annually in the US alone. Simple prevention measures save vast numbers of birds.

Key Facts

An estimated 100 million birds die in window collisions in the UK annually
Birds cannot perceive glass as a barrier - they see the reflection of sky and vegetation
Predator decals are largely ineffective - the pattern must cover the whole window
UV-reflective glass can reduce collisions by 70-90%
Collisions peak in spring and autumn migration and after fledglings leave the nest

Welfare Considerations

Window collisions cause acute traumatic injury. Birds that do not die immediately suffer concussion, internal bleeding, and spinal injuries. Dazed birds left on the ground are vulnerable to predation by cats and foxes while unconscious. The aggregate welfare impact - hundreds of millions of birds annually - is enormous and almost entirely preventable. Simple measures applied to the most hazardous windows - those with clear through-views or positioned near feeders - dramatically reduce collision mortality. Urban birds are particularly vulnerable due to high glass building density.

What You Can Do

Apply bird-safe window film or tape in a grid pattern on hazardous windows
Move bird feeders to within 1m of windows (birds cannot build fatal speed) or 10m away
Use UV-reflective glass in new building construction
Place window bird stickers densely - not just two decals in the corner
Report window collision mortalities to BTO Garden Bird Watch to help quantify the problem