Migratory Bird Welfare: Window Strike Prevention

Window strikes kill an estimated one billion birds annually in North America alone, making buildings one of the leading human-caused threats to wild bird welfare and population stability.

Key Facts

An estimated 100 million to 1 billion birds die annually from window strikes in the US
Birds cannot perceive glass as a barrier and fly into reflections of sky and vegetation
Low-rise residential buildings cause more cumulative strikes than tall commercial buildings
Fritted or patterned glass with markings spaced less than 5 cm apart effectively deters strikes
UV-reflective films invisible to humans but visible to birds are another effective solution
Most strike survivors that appear stunned still suffer internal injuries and die within hours

Welfare Considerations

Window strikes cause immediate trauma and suffering to billions of birds annually. Most victims that survive the initial impact suffer internal bleeding, brain injury, or spinal damage that leads to death within hours. The scale of this mortality is one of the most under-appreciated wildlife welfare crises. Solutions are readily available: patterned glass, external screens, UV-reflective films, and simply moving bird feeders far from windows. Building codes in some jurisdictions now require bird-safe glazing in new construction.

What You Can Do

Apply bird-safe window films or external screens on your most reflective windows
Move bird feeders either within 1 meter or more than 10 meters from windows
Support building codes that require bird-safe glazing in new construction
If a bird strikes your window, keep it in a ventilated box in a quiet dark space and contact wildlife rehabilitation