Powdermill Nature Reserve


Full view of the tunnel with the interchangeable glass panels at the left end. A protective net prevents birds from hitting the glass
(click for larger view)

Window Strike Project

It is estimated that at least 100 million birds are killed every year in the United States after colliding with windows, because birds don’t understand glass as a barrier to flight. In collaboration with Dr. Christine Sheppard of American Bird Conservancy, Powdermill has been working on a project to learn how to prevent birds from flying into glass. Thanks to grants from the American Association of Zoos and Aquariums and from Colcom Foundation, Powdermill has overseen the construction and operation of an experimental flight tunnel in our avian research area.

The wooden tunnel, about 22 feet long, is made with two panels of removable glass mounted adjacent to one another at one end of the tunnel. The two panels consist of one pane of plain, clear glass that birds can’t see and one pane of test glass in various patterns. After each bird is banded in the nearby banding lab, it is released into the tunnel. The bird is in the dark, with a perceived escape route through one of the two panes of glass at the other end, which is open to the light. A fine net inside protects the bird from actually flying into the glass. The tunnel operator scores whether the bird flew toward the plain glass or the test glass, releasing the bird after one trial. About 80 birds are tested for each pattern. The more birds fly towards the plain glass, the higher the effectiveness score of the test material.


Amy and Marcia preparing to release a bird into the tunnel
(click for larger view)

Designed with the safety of birds as a top priority, the tunnel provides an excellent means for determining which patterns are both effective at preventing fatal bird strikes and unobtrusive for humans looking through the glass. For more information on this issue, see collisions.abcbirds.org. You may also download a flyer listing simple solutions for home windows.

With the data that is collected, Powdermill can provide valuable information to manufacturers of window glass, architects, and homeowners to make buildings more bird-friendly. Our research was recently featured on NPR and Discovery Channel Canada.