Glass windows in all types of buildings, in a range of locations – cities, suburbs, and rural areas – are a fatal hazard for birds. Scientists currently estimate that 100 million to 1 billion birds are killed by collisions with glass each year in the United States alone. On a global scale, billions of birds are killed by collisions annually. This is a global wildlife crisis, impacting bird populations wherever glass is used, and its scope continues to increase. Much remains unknown about the science underlying this threat to birds. The limited knowledge about the underlying science of this phenomenon is a major impediment to the development of effective design solutions.