U of M, San Diego Zoo test window film on campus to slow bird collisions

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Strips of film that are essentially invisible to humans may help prevent birds from crashing into glass windows – but research into the method is lacking.

So the University of Minnesota and San Diego Zoo teamed up for a study on the U's campus, to help determine how promising the strips might be.

It's basically a window film, with strips of UV-reflective material, the University of Minnesota said in a news release. (Birds can see UV light, humans can't.)


The hope is that birds see the strips and realize they have to go around it, while also not restricting humans' view through the glass.

How well it will work isn't really known. Up until now, the U says, tests with the UV strips have been "artificial" – this will be the first "real-world" test of its effectiveness.

Minnesota’s Audubon Society says that birds are vulnerable from glass buildings during the day as they do not always appear as obstacles on flightpaths. At night, lit-up glass buildings attract birds that are flying.

The UV film is in three spots on the Minneapolis and St. Paul campus – the most deadly areas on campus, U technician Stephanie Beard said:

  • The skyway between Blegen Hall and Social Sciences Hall;
  • And on north-facing windows at Coffey Hall and Ruttan Hall.

In addition to the film, there are shock sensors and video cameras to help record and analyze data. And nearby windows were untreated (either with non-UV film, or no film at all) to help compare results.

The Star Tribune spoke more with Beard about the project. KARE says the strips will stay in place for a couple years.

Why is this a concern?

Approximately 988 million birds die annually in the U.S. as a result of crashing into buildings, some researchers say.

And the University of Minnesota campus sits right near the Mississippi River, part of a repeatedly used route (called the Mississippi Flyway) for millions of migrating birds every year. That ups the chance of a collision.

Sharon Stiteler, who you might know by her moniker Birdchick, has written about this in the past, when questions about the new Vikings stadium and its bird-safety measures were brought up.

In the post, she included this photo:

The blue spots are flocks of birds, so big they get picked up on radar. And as she points out, there's a giant blue spot right over the Twin Cities region.

The Audobon Society has said volunteers have noted more than 125 different species of native migratory birds that have fatally collided with downtown Twin Cities buildings since 2007.

On Twitter, Stiteler called the U of M study a "step in the right direction."


A study by the University of Minnesota’s Bell Museum of Natural History found that 44 percent of all bird deaths in St. Paul were caused by just two buildings along the migratory path it was monitoring, while in Minneapolis two buildings accounted for 67 percent of deaths.

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