Turning off lights is another important step people can take to help birds, and not just in windows. Lights draw in and disorient birds. Experts recommend using a motion sensor for outdoor lighting, especially floodlights,.
Still, most strikes occur during the day, according to the American Bird Conservancy, and while people often assume that high-rises are largely to blame, homes and low-rise buildings account for the vast majority of collisions.
Many residents don’t realize that birds are crashing into their windows. The animals may fly away before succumbing to their injuries, or a cat might grab the body before a person discovers it. During the pandemic, reports of bird strikes increased sharply because people were suddenly at home to see or hear more of them.
To study the effectiveness of placing material on the inside versus outside of windows, Dr. Swaddle and his team used zebra finches, protecting them from impact with a fine mesh in front of the glass. The domesticated songbirds see and fly like wild ones, he said, but provide more realistic results because they aren’t panicking when released. When used on the outside of glass, the two products they tested increased window avoidance by as much as 47 percent. Inside, they were ineffective. One was invisible to humans and the other used a pattern of tiny orange and black diamonds.
The project received some funding from a company that makes one of the window films that was tested. It had “no role in study design, data collection and analysis, decision to publish or preparation of the manuscript,” the authors wrote.
“The study is solid,” said Scott R. Loss, a professor of ecology at Oklahoma State University who has studied birds and window collisions extensively and who was not involved in the research. In the past, when homeowners and property managers have asked if they can apply treatments to the inside, he has urged against it but has never had a peer-reviewed study to support his position.
“This is a really good contribution that we’ll be able to point to now,” he said.