Bird-window collisions kill an estimated 600 million birds annually in the USA alone representing one of the largest preventable sources of bird mortality.
Window strikes cause an underappreciated scale of bird suffering invisible to most people. Birds that collide experience acute trauma from immediate death to concussion and slow death from internal haemorrhage. Preventive measures are well-established, affordable, and aesthetically acceptable. Individual households can eliminate window strike risk with minimal cost. Building-scale solutions require architectural specification increasingly driven by green building certification requirements.