Window strikes kill an estimated 600 million birds annually in the US alone, making building glass one of the largest human-caused sources of bird mortality, with welfare implications for the billions of birds experiencing traumatic collision injuries.
Window strike welfare harm is among the most preventable of human-caused wildlife deaths. Birds that survive initial collision often experience internal hemorrhage, brain injury, and disorientation that results in predation or delayed death. Immediate survivors that appear stunned frequently die within hours from internal injuries. The scale — hundreds of millions of deaths annually — makes window strike prevention one of the highest-impact individual actions for wild bird welfare available to building owners. The solutions are now well-established: external tape patterns, collision-deterrent films, and specially designed glass all reduce strikes dramatically. Building design standards requiring bird-friendly glass represent the most scalable intervention — requiring manufacturers and builders to address the problem at construction rather than relying on retrofit solutions.