Birds striking glass windows kill hundreds of millions to a billion birds annually in North America alone. Simple solutions dramatically reduce this preventable source of mortality.
Window collision mortality is one of the largest sources of human-caused bird death globally, yet it receives far less attention than wind turbines or cats — both of which cause significantly fewer deaths in most regions. Birds that hit windows experience blunt trauma ranging from momentary stun to skull fracture and internal bleeding. Many that appear stunned die within hours from internal injury. The solutions are well-established: external screens or netting, UV-reflective decals visible to birds but not humans, closely-spaced tape strips, and fritted or etched glass all substantially reduce collision rates. These solutions are available at relatively low cost for most residential and commercial buildings.