Walking the walk for those who fly

Making refuge buildings — and our homes — safer for birds

During summer of 2021, Christine Fox participated in the U.S. Fish and Wildlife Service’s Directorate Fellows Program, working for our Migratory Birds Division. She reflects on her fellowship and how it led to a home-improvement project that was for the birds.


I heard the sound from the next room, and my heart sank. I rushed to the glass back door in search of the feathered victim that collided with it, but the only evidence was a small gray feather on the ground. I was relieved the bird had survived the collision and flown off, naively believing it was fine.

a sleek gray bird perched on a bare branch
The gray catbird is one of the most common species killed in window collisions. Mike Carlo/USFWS

This was last April, during the peak of spring migration in my area of North Carolina. Since then, while conducting research for my fellowship project, I learned that 365 to 988 million birds die from window collisions each year in the United States.

While most victims of window strikes are found dead on the ground, many survive the initial collision but die later from internal injuries or being weakened by the force of impact. I think back to the bird that collided with my glass door and wonder about its fate.

Taking a nose-dive

Nearly three billion birds — a staggering figure — have been lost in the United States and Canada since 1970. That’s one in four gone from the population. While there are numerous causes of this decline, window collisions are a major contributor.

I was surprised to learn that the reflective properties of windows are what cause birds to fly into them. Birds see the surrounding habitat of sky or trees reflected in the window and fly towards it, resulting in a collision.

Photo of large window with sky and vegetation reflected.
Birds mistake reflections in windows for the real thing. USFWS

Reflections aren’t the only cause of collisions, though.

Interior and exterior lights can disorient night-migrating birds, leading them to collide with buildings. Towers with non-flashing lights also confuse birds in the dark, resulting in impacts with the towers or supporting guy wires.

These worrisome findings prompted the Service to support the 3 Billion Birds initiative, a concentrated effort to address the issues causing bird population decline.

Looking in the mirror

We recognized that our buildings are possible risks for bird-window collisions and need to be assessed and retrofitted. Because we manage thousands of buildings at 568 national wildlife refuges and 70 national fish hatcheries across the country, we decided a survey that could be easily accessed and used by onsite staff would be the most efficient tool to assess our impact. We used geographic information system (GIS) software to connect survey questions with building locations on an interactive map.

For my fellowship project, I spent the summer with two other passionate women piloting the survey, assessing 155 buildings at 24 national wildlife refuges. I felt incredibly lucky to visit Patuxent Research, Cape May, E.B. Forsythe, Great Swamp, John Heinz at Tinicum, Occoquan Bay, and Elizabeth Hartsell Mason Neck refuges.

Christine in front of visitor center
As part of her fellowship, Fox visited Patuxent Research Refuge in Maryland to pilot the bird-window collision survey she developed. USFWS

I discovered no two refuge buildings are alike, and each poses its own unique risks to birds. One building had already been retrofitted with preventative window film but was brightly lit at night. Another had untreated big bay windows next to a meadow teeming with birds but had minimal night lighting, with time-controlled, shielded lights in its parking lots.

One refuge was trying to prevent window collisions with bird-silhouette decals, but they were spaced too far apart. Window treatments such as decals, dots, and lines are only effective if applied in a two-inch by two-inch or two-inch by four-inch pattern. Otherwise, birds will try to fly through the gaps.

After completing our surveys, we wrote a tailored recommendation report for each refuge, to assist with retrofitting windows and improving lighting schemes. Refuge staff were eager to incorporate our recommendations.

The lesson hits home

As I wrote the recommendation reports, I realized I needed to address bird collisions at my own home. I recently purchased and installed dot tape in a two-inch by two-inch pattern, effectively deterring birds from colliding with my windows. I have also been more conscientious about turning off external lights at night.

glass doors covered in white dots
Christine Fox applied what she’d learned during her fellowship to her own home by installing dot tape in a two-inch by two-inch pattern. USFWS

In addition to applying tape patterns or film, homeowners can paint beautiful designs with tempera paint on a window’s exterior, install insect screens, or hang paracord zen curtains. The American Bird Conservancy has a comprehensive list of window treatment options.

Last summer was incredible. Not only did I get to work with an amazing team of people and visit beautiful national wildlife refuges, I helped develop a program that will have a lasting positive impact on birds.

Learn more about window collisions and the Service’s efforts to prevent them.



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U.S. Fish & Wildlife Service Northeast Region

U.S. Fish & Wildlife Service Northeast Region

Conserving wildlife and habitats from Maine to Virginia, New York, and Pennsylvania.