Up to one billion birds die from window collisions in North America alone each year, making glass buildings one of the largest human-caused sources of bird mortality.
Window strikes cause acute trauma including brain hemorrhage, broken necks, and internal injuries. Birds that do not die immediately may survive in a stunned state for hours before succumbing to injuries or predation. The suffering is widespread, distributed across billions of individual animals. The good news is that this is one of the most tractable bird welfare problems: simple, affordable interventions can reduce collisions by over 90% in affected windows.