Glass Collisions

Research & Testing

Powdermill Avian Research Center, PA, USA ©Christine Sheppard

Bird-friendly glass has patterns that make birds change course instead of colliding with it. Many of these patterns are never noticed by people but still save birds' lives.

The difficulty? It is impossible to directly ask a bird what it can see.

Instead, ABC's Tunnel Testing Program tells us how birds react to patterns on glass, information that is used to identify new glass and retrofit products that prevent collisions.


About the Tunnel Test

We test birds' reactions to patterned glass by asking them to decide whether to exit the tunnel via an “invisible” panel of plain glass or the patterned material being tested. A net safely stops the birds before they hit the glass.


Powdermill Video

See the Powdermill Tunnel in action! Discover Canada created this short film about ABC's glass evaluation program.


About the Rating System

ABC's rating system assigns a “Threat Factor” or TF score, to materials tested in the tunnel. Low TFs indicate materials that most birds avoided in the tunnel.


Contact Us

To request glass testing or learn more, please contact Christine Sheppard, Director, ABC Glass Collisions Program.