Wild Bird Window Collision Prevention

Up to a billion birds die annually from window collisions in North America alone, making glazed buildings one of the most significant human-caused bird welfare threats.

Key Facts

An estimated 600 million to 1 billion birds die from window collisions in the US annually
Birds cannot perceive glass as a barrier and fly toward reflections of vegetation and sky
Treated glass with ultraviolet patterns is visible to birds but transparent to human eyes
Simple external measures including decals, screens, and tape patterns significantly reduce collisions
Most window strike fatalities are small songbirds, many of which are already in population decline

Welfare Considerations

Window strikes cause acute trauma injuries: broken bones, internal haemorrhage, and brain injury. Many birds die immediately; others survive for hours or days before succumbing to internal injuries. The scale — hundreds of millions of deaths annually in North America alone — makes this one of the numerically largest sources of human-caused bird suffering. Prevention is achievable at modest cost: external screens, UV-treated glass, and visual markers applied in patterns of 5 by 10 centimetres or smaller effectively reduce collisions by 70 to 90 percent. The barriers are primarily awareness — most building owners and occupants do not know their windows are killing birds.

What You Can Do

Apply window collision prevention markers or film to high-risk windows in your home or workplace
Advocate for UV-reflective glazing requirements in new building construction
Move houseplants away from windows that birds perceive as flythrough corridors
Report and care for window-strike survivors by keeping them warm and quiet before contacting a wildlife rehabilitator