Wild Bird Window Strike Prevention

Window collisions kill hundreds of millions of birds annually in North America alone — simple preventive measures dramatically reduce this mortality.

Key Facts

An estimated 600 million birds die annually from window strikes in the US and Canada
Birds cannot perceive glass as a barrier, particularly when it reflects vegetation
Windows that reflect sky or trees are particularly dangerous during migration
Simple markings on the outside of glass at 2-inch spacing prevent most window strikes
Window feeder placement very close to glass actually reduces rather than increases collision risk

Welfare Considerations

Window collision mortality represents the second leading human-associated cause of bird death after outdoor cats in North America. The welfare harm involves both immediate mortality and injuries that require rehabilitation or result in delayed death. Prevention is straightforward and inexpensive — applying visual markers to the outside surface of glass at appropriate spacing allows birds to perceive the barrier and avoid it. The challenge is awareness — most window strikes are not witnessed by occupants and the scale of mortality is thus underappreciated. Simple products and DIY solutions are available that maintain window aesthetics while providing effective collision prevention.

What You Can Do

Apply external window markings at 2-inch or smaller spacing to prevent bird strikes
Move bird feeders to within 3 feet of windows to prevent fatal collision velocities
Turn off or reduce lights visible from windows during migration seasons
Install bird-friendly glazing in new construction or window replacements
Share window strike prevention information with neighbors and building managers