Window strikes kill an estimated 600 million birds annually in the United States, making building glass one of the leading human-caused sources of bird mortality.
Birds striking windows at speed experience concussion, internal hemorrhage, and broken bones. Many die immediately; survivors may appear stunned but die hours later from internal injuries. The stress of capture for rehabilitation compounds the initial trauma. Building glass is a welfare problem at massive scale that is largely invisible to building occupants. Simple, inexpensive solutions including external screens, UV-reflective films, and exterior strings reduce strikes dramatically without significantly affecting building aesthetics.