Bird Window Collisions

Bird-Window Collisions: Why Glaziers and Architects Should Care

Architects/Glaziers/General Contractors

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Bird Window CollisionsYou’ve probably seen it happen. A bird flies smack into a window, completely unaware of its impending doom. While it’s not as big of a concern in single-family homes, glass-clad office buildings are estimated to be the cause of up to 988 million bird deaths each year — almost 10% of the bird population. Towering skyscrapers, however, are not the real issue, causing only 1% of bird-window collisions. Most bird-window collisions actually occur on buildings less than 11 stories tall and even a first floor glass atrium with trees emulating the outside environment can spell danger for birds.

So what can be done? Glass is an integral material in architecture, providing more visibility, light, and beautification of spaces. Bird deaths, unfortunately, are not going to eliminate, or even lessen, its usage.

What Causes Bird-Window Collisions?

The Michigan Tech student chapter of The Wildlife Society, along with 40 other universities in Mexico and the United States, are currently researching ways to reduce bird-window collisions. By studying buildings on campus, students have learned that how much a window reflects surrounding trees and how transparent it is makes a difference for daytime collisions.

Nighttime collisions are also an issue, particularly during migration season. Because birds use natural light from the moon or stars to navigate, brightly illuminated cities and neighborhoods interfere with this behavior by letting artificial light leak into the atmosphere. The birds can get trapped in these light sources, become disoriented and avoid entering a dark area. Located between two migratory areas, it’s estimated that close to 1 million bird deaths occur per year in the city of Toronto, alone.

How Architects and Glaziers can Reduce Bird-Window Collisions

Some might argue that preventing bird-window collisions isn’t an issue for an architect or the glass industry. There have been rumblings, however, that the Environmental Protection Agency (EPA) could step in and create new restrictions. Dialogue on this topic includes the thought that, at least as far as birds are concerned, glass reflectivity is a form of radiation that requires regulation to protect the bird population.

In Canada, the Fatal Light Awareness Program (FLAP) is researching effective methods of reducing bird-window collisions because previously tested measures, such as noisemakers or plastic owls, just don’t work. The best solution so far is a UV marker on the glass that is invisible to the human eye, but is viewed as a solid object by birds.

Other potentially effective methods of reducing bird-window collisions include:

  • Antireflective vinyl or polyester films applied over the entire glass or in a uniform pattern
  • Vinyl static clings, etched window decals or tempera paint can be used to create a uniform pattern across the glass
  • Bird screen hung loosely in front of windows

Next Steps:

Make or Break Project

Image Courtesy of Ted (Flickr: DSC_0075) [CC-BY-SA-2.0 (], via Wikimedia Commons

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