Is your community a safe place for birds? Has there been a study of bird deaths due to collisions with buildings?
In 2021 Treehugger editorial director Melissa Breyer founded 226 dead birds at the World Trade Center one morning. Most were likely killed by mid-flight collisions with the building’s many glass facades.
Ornithologists report that most daytime bird collisions occur in the lowest 250 feet of buildings, largely due to the reflections of vegetation and the sky in glass windows and facades. At night, migrating birds flying at higher altitudes may be forced to descend because of stormy weather. “Searching for celestial clues to aid in wayfinding, these birds frequently encircle illuminated cities and fall victim to disorientation, predation, or collisions with backlit windows.”
Bird-Safe Building Guidelines, originally published by NYC Audubon and expanded upon by the American Bird Conservancy, recommend bird-safety changes that have other environmental benefits as well.
Turning lights off in buildings to help birds navigate more effectively also reduces light pollution and saves energy. The study also noted that the United States wastes “over one billion dollars in electricity costs annually because poorly designed or improperly installed outdoor fixtures allow much of the lighting to go up to the sky,” which further confuses migrating birds.
“At Chicago’s McCormick Place exhibition hall, which sits next to Lake Michigan, researchers recorded a 60 percent drop in collision-related bird deaths when lights were turned off for just half of the night.”
“At the level of design, reducing the amount of glass used on building facades has a positive effect on bird populations and the broader environment, decreasing reflectivity as well as solar heat gain. Patterned or textured glass that makes its presence as a solid surface more obvious to avian species is also highly effective, according to NYC Audubon. “
In NYC, “a new law means that all new construction, or replacements of exterior glazing, will have to use bird-friendly materials from street level up to 75 feet, as well as on any parallel glass walls, glass handrails or wind breaks, and adjacent to any green roofs. The American Bird Conservancy has a handy guide to materials, including ceramic frit that can be baked on to glass in a variety of designs as well as UV-reflecting patterns, thin screens and dense solar shades.”
Might you and a few friends check out the bird deaths due to building collisions in your city? If the number seems high, you could recommend safety changes to reduce the death rate.