Wildlife Conservation

Window Strikes: A Preventable Cause of Bird Death

Glass windows kill an estimated 600 million to 1 billion birds annually in North America alone. Simple and inexpensive measures can dramatically reduce this toll.

Key Facts

Birds see glass reflections as real sky or vegetation and fly into them at full speed
600 million to 1 billion birds die from window strikes annually in the US alone
Collision is the second leading human-caused cause of bird mortality after outdoor cats
Migratory birds at night are especially vulnerable to lit glass buildings
Bird-safe glass with UV-reflecting patterns is now commercially available

Welfare Considerations

Window strikes cause traumatic brain injury, internal bleeding, and neck fracture. Birds that fly off after a strike often die hours later from internal injuries. The sudden violence of the impact represents acute suffering at massive scale. Because most deaths go unnoticed, the welfare impact is chronically underappreciated.

What You Can Do

Apply bird-safe window films or decals to large windows — spacing matters (under 5cm)
Turn off unnecessary lights during spring and fall migration nights
Report window strike mortalities to the American Bird Conservancy bird-friendly building database
Advocate for bird-safe building design in local planning codes and new construction