Wildlife

Wild Bird Window Strikes: Scale and Solutions

Glass collisions kill up to a billion birds annually in North America alone, making windows one of the leading human-caused bird mortality factors.

Key Facts

An estimated 600 million to 1 billion birds die from window strikes yearly in North America
Most strikes occur at residential buildings not skyscrapers
Birds cannot perceive glass as a barrier or detect reflections as artificial
Simple deterrents reduce strikes by over 90% when properly applied

Welfare Considerations

Birds that survive initial impacts often die hours later from internal hemorrhage and brain injury. Stunned birds left on the ground face secondary predation. The cumulative mortality affects population viability of already-declining species.

What You Can Do

Apply visual markers spaced no more than 5 cm apart on exterior glass
Use collision-deterrent window films that reflect ultraviolet light visible to birds
Keep feeders either within 1 m or beyond 10 m of windows to reduce strike risk
Report strikes to citizen science databases to help researchers map hotspots