No product can be guaranteed to stop all collisions in real world conditions. Glass can vary in appearance from one façade of a building to another or with time of day, depending on solar angle, reflected environment and other factors. The Threat Factor number is determined under standard conditions and does not capture that variety. Instead, Threat Factor is a relative index, and products with lower TFs are considered more effective at preventing collisions. A TF of 30 suggests that collisions will be reduced by at least 50 percent and is ABC's upper threshold for recommending a product. Products with UV patterns should be considered carefully for some applications: Materials with ultra-violet patterns will vary in effectiveness with the amount of UV light present. This means that when the UV index is low – under low light conditions in early morning or evening or if the glass is shaded, or when it is overcast – UV patterns will be less visible to birds. In addition, not all types of birds can see UV. For example, songbirds can see UV, raptors and pigeons cannot. Because Threat Factors can be effected by low-e coatings, published Threat Factors apply only to the glass assembly tested.
Any wood without reflective paint
any vinyl that is not reflective
Tunnel tested at Hohenau-Ringelsdorf Biological Station
Surface 1, orange and black vertical lines
non-reflective white surface
This window film creates a solid appearance from the outside, but allows views from the inside and can reduce glare and cooling costs while protecting birds.
White Collidescape was one of the first bird-friendly solutions available and there is extensive evidence that it stops collisons almost completely - while still allowing a view out the window.
Vertical stripes composed of a grid of nine mm black dots spaced 1mm apart. Stripes are 75 mm apart
Tested as monolithic panel at Hohenau-Ringelsdorf Biological Station
These “Zen Wind Curtains” are easy to install, long lasting and highly effective. The BirdSavers website gives directions to build your own, or order from them from the Acopian BirdSavers website. A lengthy history shows they work extremely well.
Tunnel tested at Hohenau-Ringelsdorf Biological Station
dull metal surface, prescriptive rating
