Urban Bird Welfare - Window Strikes

Window strikes kill an estimated 100-1 billion birds annually in North America alone. This largely preventable cause of bird mortality and injury represents one of the most tractable welfare problems in urban environments.

Key Facts

Window strikes kill an estimated 100 million to 1 billion birds annually in the United States
Birds cannot perceive glass as a barrier, especially when it reflects sky or vegetation
Migration periods and seasonal movement increase strike risk as birds are less familiar with local structures
Fritted glass and external window decals with patterns spaced 5cm or less apart are effective deterrents
Outdoor cats, communication towers, and vehicles also cause significant bird mortality but windows are often the largest category

Welfare Considerations

Window strike welfare harm is acute - birds that are struck experience traumatic brain injury, internal bleeding, and often die shortly after impact. Many birds that appear stunned and recover actually die from internal injuries over the following days. The scale of mortality makes this one of the most significant anthropogenic causes of bird death globally. Reducing window strike mortality is highly tractable - products including patterned window films, external nets, and UV-reflective decals are effective and increasingly affordable.

What You Can Do

Apply window deterrent film or decals to large windows, especially those facing gardens or trees
Place bird feeders either very close to windows (under 1 meter) or well away from them (over 10 meters)
Report window strike collisions to wildlife organizations to contribute to mortality monitoring
Advocate for bird-safe glass standards in new building construction and planning regulations