Building windows kill an estimated 600 million birds annually in the US alone — a preventable welfare and conservation crisis.
Window collisions cause traumatic deaths — brain injuries, broken necks, and internal hemorrhage. Birds that survive the initial impact often die later from delayed injuries. The scale is enormous: hundreds of millions annually in the US alone. Solutions are inexpensive and aesthetically unobtrusive. This is a welfare problem where individual action at low cost can prevent enormous harm.