Window glass on homes, low rise buildings and high-rise buildings poses one of the most common hazards for birds in the built environment. Researchers estimate that up to 1 billion birds die every year in the United States alone from colliding with a window—this makes window collisions one of the top three threats to wild bird populations, third only to habitat destruction and cats. Yet, as awareness has grown, solutions have been developed that can be used at the commercial scale and at the residential scale to reduce this deadly hazard.
Birds do not recognize glass as a solid object. To a bird, the reflections on glass look like a continuation of habitat, something they should be able to fly right through. As a result, collisions can occur anywhere that unmarked glass is used — on large and small windows, as well as on reflective and transparent panes. All birds are at risk; one collision can cause the injury or death of an otherwise healthy bird.
Nearly half of all window strikes occur at residential houses (44%), and over half at low-rise buildings (56%). Fewer than 1% occur at high rise buildings. That’s because there are 123 million residential homes across the nation, and 15 million low-rise buildings, compared with only 22,000 high rises.
That means that in order to save birds from window collisions, this hazard needs to be addressed at all scales of development.