Window strikes kill hundreds of millions of birds annually worldwide; simple prevention measures dramatically reduce collision mortality and injury.
Window strikes cause acute physical trauma — concussion, internal bleeding, and fractures — that may result in immediate death or prolonged recovery. Birds that appear to have recovered from window strikes may have sustained internal injuries that cause delayed death. Prevention is straightforward and effective: window markers, screens, or patterned glass that birds can see as a barrier rather than open space. First aid for stunned birds includes providing a secure dark container and allowing quiet recovery before release.