Glass windows kill hundreds of millions of birds annually in North America alone. Simple, low-cost interventions can dramatically reduce this preventable source of mortality and suffering.
Window strikes cause both instant death and prolonged suffering. Birds that strike at high speed and do not die immediately may suffer from cerebral hemorrhage, internal bleeding, and traumatic brain injury, dying slowly over hours in an exposed position. The suffering of birds that survive impact but are too injured to fly — vulnerable on the ground to predators and weather — can be significant. The scale of mortality makes this one of the largest direct human-caused sources of bird death. Prevention is straightforward and inexpensive; the primary barrier is awareness. Building design codes that mandate bird-safe glass represent a systemic solution that could prevent tens of millions of deaths annually.