Rigorous scientific testing has shown that two popular UV products, Dr. Kolbe Birdpen®1 and Dr. Kolbe Birdsticker®2, are essentially useless for preventing bird collisions.
Further, we strongly advise against any UV products, including expensive glass and window films with embedded patterns that reflect or absorb UV light. Their claims of effectiveness are at best overly optimistic interpretations of scant data.3
The idea behind all UV products is that are visible to birds but invisible to humans. Unfortunately, many bird species can’t see UV light, or can’t see it well enough4 for these products to work. (Read this research study for an excellent scientific explanation.)
Furthermore, UV light levels are lowest at the times of day when birds are most active, namely early in the morning. This means that, even for bird that can see UV light, these products are least effective just when they’re most needed.
A good rule of thumb is: If we can’t see it, neither can birds.
- Rössler, Martin. 2015. Bird collisions with glass surfaces – Test report birdpen®. Test according to ONR
191040 and WIN-Test in the flight tunnel II of the Biological Station Hohenau-Ringelsdorf. ↩︎ - Rössler, Martin, DI. 2018. “Bird collisions on glass surfaces – Dr. Kolbe Birdsticker® test report”, test
including reflections in Flight Tunnel II of the Hohenau-Ringelsdorf Biological Station, on behalf of the
Swiss Ornithological Institute in Sempach, February 2018. ↩︎ - Swaddle JP, Emerson LC, Thady RG, Boycott TJ. 2020. Ultraviolet-reflective film applied to windows
reduces the likelihood of collisions for two species of songbird. PeerJ 8:e9926.https://doi.org/10.7717/peerj.9926 ↩︎ - Håstad O, Ödeen A. 2014. A vision physiological estimation of ultraviolet window marking visibility to birds. PeerJ 2:e621 https://doi.org/10.7717/peerj.621 ↩︎