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Why are there fewer bird-glass collisions on WMU campus?

Bridgeway between Wood Hall and Chemistry.  On the south side of the walkway you can see dots on the windows, but the windows on the other side are clear.  A student in a brown jacket and dark backpack walks under the bridge.
Leona Larson
/
WMUK
The walkway between Wood Hall and the Chemistry Building. Sheets of dots were applied to the outside of the south side of the walkway. The bird-safe mitigation efforts has significantly reduced the number of bird strikes at this location.

Spring migratory birds take wing, but many will hit glass windows. On WMU's campus, someone is keeping count.

Up to a billion birds die each year in the United States after flying into windows. Half of them will hit home windows, according to a widely cited 2014 study.

In 2021, WMUK News Director Sehvilla Mann recorded a video of a cardinal screeching outside WMUK studios during her lunch hour.

“It’s been tripping continuously for a minute. I think maybe it’s upset about this one here that seems to have hit the glass and died,” Mann said in the recording.

Hours later, when she left for the day, the cardinal was still at it. It was the second dead bird she’d seen in as many months under the glass three-story walkway between Friedmann and Dunbar Halls at Western Michigan University.

Gail Walter is a retired veterinarian and conservation volunteer. She said what Mann witnessed is common bird behavior.

Walter speed walks campus daily during the spring and fall migration; in April, May, September and October. She counts dead birds on her walk.

I caught up with her last week, walking around glass buildings and under glass walkway bridges. She stopped at the glass walkway between the Miller parking structure and the Richmond Center. She said the glass walkway bridges are particularly dangerous for birds. This is one of the worst on campus. That’s because birds can’t tell the difference between reflection and reality.

“This is very confusing for birds. They can see through it. They don’t know that there’s glass here. They don’t recognize this is not a passageway. They also see the clouds and the trees and the structures that are reflected on the outside surface of the glass.”

Walter said the worst site for bird-glass collisions on campus is the College of Health and Human Services. It is essentially a glass building. But Western is working to reduce bird-glass collisions. The university is installing bird-safe glass in the new Dunbar Hall. It has applied tape and decals on the outside glass in other areas, like the curious dots on the south side of the glass bridge between Wood Hall and the Chemistry building. We wondered why the university applied it only on one side.

“My recommendation is always to do both sides, you really have to do both sides, because the birds can see through it,” Walter said.

Walter said WMU received a grant to do the whole bridge before the pandemic shutdown, but supply chain issues and price hikes made the project too expensive. When it came to deciding what to do, Walter’s dead bird count offered a practical solution.

“In this particular case, I knew that the birds are hitting this side. And if we do that, just the south side, we can stop 90% of the collisions.”

Since WMU installed the sheets of dots on the south side of the bridgeway last year, Walter’s found only one dead hummingbird on the north side of the bridge.

There are no plans to mitigate the walkway between Friedmann and Dunbar where at least two dead birds were found two years ago. Where measures are taken, Walter said, it works. She’s counted fewer dead birds over the last two years. But mitigation efforts aren’t the only reason why.

“I think that’s because the bird populations have declined so much that we that there’s fewer birds in the world to collide with things which is really kind of sad.”

Homeowners can help. That 2014 study found half of the birds that strike windows, hit home windows. Walter said decals, tape or tempera paint are things you can do to the outside of your windows to keep the view and save the birds.

“It has to be on the outside, because otherwise, the birds still see the reflection of the clouds and vegetation. And they think that they're flying to someplace, an environment that's safe.”

It’s particularly important if you have a bird feeder.

“There’s no safe distance between a bird feeder and a window,” she said. “Birds can collide with a window no matter where the feeder is.”

Concerned bird watchers can help with their own count. The Global Bird Collision Mapper is a web app for reporting bird-glass collisions with buildings around the world.