Advances in Window Safety Go to Cornell Lab and Cornell Campus

Every year, up to a billion birds die from window strikes in the US, species of all sizes brought down by the invisible tragedy of glass. A growing body of research surrounding the severity of window collisions—and ways to prevent them—has resulted in more organizations moving toward birdhouses, including the Cornell Lab of Ornithology.

Built in 2002, the Lab’s home in Sapsucker Woods was designed to blend in with the landscape and allow visitors to immerse themselves in the world of birds. Its two-story structure, built with natural materials like cedar and stone, sits unobtrusively below the treeline of the surrounding 220-acre sanctuary. Overlooking the pond and feeder garden is a tall, glass-fronted observatory, featuring an 84-foot-wide, two-story expanse of windows.

Lab architects realized that these large areas of glass posed a threat to birds, but not to the extent known today: at the time of construction, there was limited research on the size of the window strikes, and the proper guidelines for preventing collisions have not yet appeared. .

“If you look at the Lab of Ornithology from the outside, you’ll see that the glass is set back from the metal pillars and framing, instead of being flush,” said Miyoko Chu, the Lab’s senior director of science communications. “From an architectural perspective, it was thought that birds could see the metal and change course before hitting the glass. But research now shows that birds don’t use the same visual cues as humans. They didn’t know there was a hard surface between the metal, so they tried to fly through it—probably like flying between trees and tree branches.”

The transparency and reflectivity of glass often causing birds to perceive windows as extensions of their habitat. Fully transparent structures such as glass bridges or breezeways allow birds to see through the trees and into the sky, and the illusion of open air results in birds striking the glass without realizing it’s there. this. Reflective windows behave similarly; birds see a mirage of trees and sky that they fly towards.

Collision avoidance techniques are centered around splitting these images of leaves. Many studies have shown that birds tend to fly through windows unless the glass is equipped with a 2-inch by 2-inch pattern to break reflections (using devices such as stickers/decals and tape, among many other options) or if the windows are made to include signals that stop collisions. These findings explain why the Lab’s original window design was largely ineffective at preventing strikes.

“To make Lab windows safer, we considered several options, evaluating factors such as aesthetics, cost, durability, and ease of installation and maintenance,” Chu said. “In the end, we chose Acopian BirdSavers, ropes that hang in front of windows, in large part because of their higher effectiveness rating from the American Bird Conservancy compared to film applied externally in patterns such as dots or stripes.

A separate option is to hang bird netting in front of the window. This approach is more effective and always covers the window overlooking the Lab’s busy feeder garden—a high-risk area in cases where startled birds can jump away from a feeder and toward a window

The Lab is now working to support bird-friendly development initiatives elsewhere on the Cornell University campus. Collaboration with campus partners and the American Bird Conservancy’s Windows Collision program has already shown results—in late August, the university published new bird-friendly design and construction standards. It will guide new construction projects to safer structures, landscaping, and window designs. Additional plans are underway to identify and address problematic structures on campus through additional monitoring and outreach.

While the severity of the collision issue is frightening, on the other hand, it is a tremendous opportunity to make changes to our buildings and help keep a billion birds alive and flying. To do so will require initiatives at universities and cities—as well as efforts at the individual level to make homes more bird-friendly.