Window strikes kill an estimated 600 million to 1 billion birds annually in North America alone, representing one of the largest human-caused sources of bird mortality with practical prevention solutions available.
Window strikes cause significant suffering beyond mortality: birds that survive initial impact often die from internal hemorrhage, brain injury, or disorientation that leads to secondary predation. Even surviving strikes may result in concussion effects lasting hours, during which birds are vulnerable to weather exposure and predators. The welfare significance of one billion annual mortality events is extraordinary — this represents an enormous preventable suffering burden. The solutions are well-established, affordable, and aesthetically compatible with building design: external window film, fritted glass patterns, and external screens. Unlike some wildlife mortality sources that require systemic industrial change, window strike prevention is achievable by individual households and building owners making concrete choices about their properties.