Tunnel Test Report Fall2023/Spring 2024
The latest test results for WindowAlert's bird-friendly glass solutions are in. The products were evaluated at Foreman’s Branch testing facility during Fall 2023 and Spring 2024.
The testing made use of a tunnel test methodology. This method involves flying at least 80 individual birds towards a tunnel containing both a test pane and a control pane, then recording which pane the birds avoid. Mist nets are used to prevent any injury to birds.
WindowAlert tested four different glass samples with varying patterns of UV liquid dots and decals, aimed at deterring bird collisions.
Here are the test results:
Threat Factor (TF): 41
Threat Factor (TF): 33
Threat Factor (TF): 17
Threat Factor (TF): 17
Notes on Test "Walert 4"
Testing for Walert 4 was begun in the fall of 2023 with 51 flights and completed in the spring of 2023 with 37 flights. The fall flights had a Threat Factor (TF): 25. The spring flights had a Threat Factor (TF): 6.
There may be a number of potential reasons for this variance. One possible, yet unsubstantiated, reason for an improved spring results is that the UV index (which impacts the reflectivity of WindowAlert products) is typically higher in the spring than the fall.
Threat Factors do not equal the percent reduction in collisions expected when a glass is installed on a building. In fact, the same glass may perform differently on each side of a building, depending on angle to the sun, habitat reflected, etc. Threat Factors are an index, reflecting the relative response to different patterns by songbirds flown in the tunnel. However, where monitoring data on tunnel tested products are available, they confirm that the lower the threat factor, the fewer collisions.
ABC Birds considers materials with a TF ≤ 30 as bird-friendly, corresponding to a reduction in collisions by at least 50%. The test results indicate that the tests Walert 3 and 4 are highly effective.
Why it matters: Bird collisions with glass are a significant conservation issue, with millions of fatalities each year. These results help refine building material choices to protect bird populations.