Collisions with glass rank second, after habitat loss, among the causes of bird deaths related to human activity. It is estimated that billions of birds die in collisions with glass surfaces every year.
Bird vision is their dominant, highly developed sense, but animals are perceptually limited. Transparent surfaces are simply invisible to them and become a deadly barrier. The most common result of a collision is immediate death (or within minutes of the collision) as a result of severing the spinal cord in the cervical region. Every glass panel is a threat: urban skyscrapers with a mirror effect, windows of blocks of flats, single-family houses, noise-absorbing screens on highways or bus-stop shelters made of glass.
Collisions of birds with glass is a phenomenon that can barely be seen with the naked eye and just a few decades ago hardly anyone was aware of its gigantic scale. Unfortunately, the growing awareness of threats does not go hand in hand with solutions which would at least limit the scale of the problem.