Wild Bird Window Strike Welfare and Prevention

Window strikes kill an estimated one billion birds annually in North America alone, with glass appearing invisible or reflecting habitat causing birds to fly into buildings at speed, causing brain injury, internal bleeding, and death.

Key Facts

An estimated 100 million to one billion birds die from window strikes annually in the USA alone
Birds struck by windows often suffer internal hemorrhage and brain injury without external signs of injury
Apparently stunned birds that seem to recover may still die hours later from delayed injury
Window treatments including UV-reflecting coatings and visual markers visible at specific spacings prevent most strikes
Dark-coloured windows reflect habitat while transparent windows cause birds to attempt to fly through to apparent habitat on the other side

Welfare Considerations

Window strikes cause significant acute welfare suffering even when not immediately fatal, with birds experiencing collision trauma, disorientation, and often prolonged dying from internal injuries. The welfare harm is entirely preventable through building design and glass treatment at a relatively modest cost. Existing buildings can be retrofitted with window films, external screens, or visual markers at appropriate spacing. The one-meter spacing recommended for markers provides effective prevention by being visible within the evasion response distance of approaching birds.

What You Can Do

Apply window films or visual markers at appropriate 5cm horizontal and 10cm vertical spacing on problem windows
Move bird feeders to within 1 metre of windows where strikes occur to reduce fatal flight speed
If you find a bird that has struck a window, place it in a ventilated box for 2 hours before release
Advocate for bird-safe building design standards in your local planning framework
Support organizations like American Bird Conservancy developing bird-safe building standards