Window strikes kill an estimated 600 million to 1 billion birds annually in the US alone, making buildings a leading cause of bird mortality. Simple solutions can dramatically reduce this toll.
Window strike welfare impact is both enormous in scale and largely invisible — most birds die or are injured without human observers present. The acute welfare harm of window strikes includes immediate death, neck fractures, brain trauma, beak injuries, and internal hemorrhaging. Birds that appear to recover after a short period often die from delayed injuries within 24-48 hours. The suffering involved in these deaths is real and significant. Prevention is highly feasible — external films, UV-reflecting patterns, and external screens are all effective. Building design codes in some cities now require bird-safe glass. The welfare case for window strike prevention is straightforward: a massive source of avoidable suffering can be substantially reduced with low-cost, low-effort interventions.