Saving Birds, One Window at a Time: The Role of Bird Protection Film
- SAGR PRODUCTS INT'L
- Apr 22
- 1 min read
4/22/25 - American Bird Conservancy & United States Geological Survey’s Bird Banding Lab. Birds collide with glass because they see the world differently than people do. These collisions kill up to 1 billion birds each year in the United States.
Since 1922, the BBL has amassed nearly 11,000 reports of banded bird collisions, including more than 900 reported in the last five years alone. While some collision victims are banded, many are not. Any banded bird that collides with glass provides a small glimpse at the serious problem of window collisions, as well as vital information for that bird's species. An estimated 44 percent of window collisions occur on residences only one to three stories high. Many birds reported after building collisions are species like Cardinals, Evening Grosbeak, Purple Finch, Mourning Dove, American Goldfinch, Common Grackle, and raptors such as Sharpshinned and Cooper’s Hawks.
Bird protection film is a specialized material applied to glass to prevent bird collisions by making the glass visible to birds. It uses visible or UV-reflective patterns that take advantage of birds’ ability to see ultraviolet light, breaking the illusion of open sky or reflected habitat. Effective designs follow the “2x4 rule,” ensuring patterns are close enough to be detected in flight. Since “bird-friendly” lacks a standard definition, the Material Threat Factor (MTF) was developed to quantify collision risk based on how birds perceive glass in different settings. MTFs are determined through controlled testing, such as tunnel tests and field trials, as real-world collision data is limited and difficult to collect.
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