Songbird Migration and Window Strike Mortality

Approximately 1 billion birds die from window strikes annually in the US alone, making glass collisions one of the leading human-caused sources of bird mortality and welfare harm.

Key Facts

An estimated 600 million to 1 billion birds die from window strikes annually in North America
Most deaths occur at low-rise buildings and homes, not skyscrapers as commonly believed
Birds see reflections of sky and vegetation and do not perceive glass as a barrier
UV-reflective window films and exterior screens are highly effective at preventing strikes
The American Bird Conservancy provides resources and certification for bird-safe building designs

Welfare Considerations

Window strikes cause acute traumatic injury that ranges from immediate death to internal trauma, concussion, and delayed death from injuries. Survivors that are stunned often die from impact injuries or predation while disoriented. The welfare scale — hundreds of millions of birds annually in North America alone — makes window strikes among the most significant sources of bird suffering caused by human infrastructure. Prevention through exterior markings, screens, or UV films is straightforward and effective, and represents a welfare improvement achievable at the household level.

What You Can Do

Apply bird-safe treatments to windows in your home using UV film or external screening
Move bird feeders to within 3 feet of windows or more than 30 feet away
Support bird-safe building design requirements in your municipality
Report window strike bird injuries to a wildlife rehabilitator for care