Researchers have tried to understand collisions and create strategies to reduce their impact on birds, documenting mortality patterns and how they are influenced by lighting, the amount of glass present, the distribution of nearby vegetation, and other variables. This science has come a long way, but many questions remain unanswered.

ABC is conducting applied research aimed at quantifying the relative threat of different materials and treatments. ABC’s program is based at the Carnegie Museum’s Powdermill Avian Research Center, near Rector, Pennsylvania. There, we test the effectiveness of commercially-available materials for deterring collisions, and investigate how to create effective patterns that cover a minimum of the glass surface.

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Testing Slideshow descriptions

1. Birds are caught in mist nets and brought to the station, where they are banded, weighed and measured.

2. Once banded, birds are brought out to ‘the tunnel’ – an apparatus 10 meters long. Birds are introduced into the tunnel and fly towards the samples being tested (a net stops them from actually hitting the glass). As they fly, they are videotaped, as well as observed by the tunnel operator.

3. Birds’ responses to different patterns and materials are tested in ‘the tunnel’, seen here. The mirrors reflect light on to the front surface of glass samples. The door (covered with black felt to stop light leakage) opens to release the bird after its flight.

4. A view of glass set up for testing in the tunnel. Birds have their choice of trying to exit the tunnel through the clear (invisible) glass or through the sample, in this case a panel of insulated, fritted glass. The score for the sample is the percentage of birds tested that fly towards the clear glass. We test a minimum of 80 birds per sample.


Similar research has been conducted by Dr. Dan Klem, at Muhlenberg College. ABC’s testing strategy is based on the work of Martin Rössler in Austria. Their papers can be found in the Bibliography section of this site. The Austrian testing protocol uses a device commonly called ‘the tunnel’ (the Powdermill tunnel is shown above). This program was developed to test free-standing glass, such as that used in highway noise barriers or “wind walls.” ABC has modified the protocol, to test glass on buildings, where light intensity behind the glass is typically many orders of magnitude less than on the front surface that birds see.

Austrian testing protocol ONR 191040
English translation of ONR 191040

See the tunnel in action! The Discovery Channel Canada checked out the project and created this video.

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