Wild Bird Window Strike Prevention

How to prevent the billions of bird deaths from window collisions each year through simple interventions.

Key Facts

Between 100 million and 1 billion birds die from window strikes annually in the United States alone
Birds cannot perceive glass as a barrier and fly into reflections of sky and vegetation
Windows on the ground and second floors cause the most strikes because birds are flying at these heights
Patterns applied to glass at intervals of 5cm or less (the two-inch rule) effectively prevent bird strikes
Interior plants positioned near windows increase strike risk by attracting birds toward apparent habitat

Welfare Considerations

Window strikes kill birds instantaneously in severe collisions but also cause concussions, spinal injuries, and internal bleeding in birds that appear to survive the initial impact. Many stunned birds found on the ground after strikes die within hours from internal injuries. The welfare scale of this problem is extraordinary — the death toll from window collisions rivals hunting, cat predation, and vehicle strikes combined as a cause of bird mortality. Prevention is inexpensive and widely accessible: window films, external screens, decorative glass treatments, and angled window installation all substantially reduce strikes. This is one of the highest-impact, lowest-cost wildlife welfare interventions available to individual households.

What You Can Do

Apply window decals, UV-reflective film, or external screens to high-risk windows at your home
Follow the two-inch rule: pattern coverage must be 5cm apart horizontally and 10cm vertically to be effective
Move bird feeders to within 30cm of windows (too close for fatal acceleration) or over 10 meters away
If you find a stunned bird, place it in a dark cardboard box and contact a wildlife rehabilitator
Advocate for bird-safe building standards in new construction and major renovations