University of Minnesota tests reflective film to head off bird collisions

Stephanie Beard knows where the most dangerous places are at the University of Minnesota — at least for birds. For years, the veterinary technician has been tracking their unfortunate collisions with windows on the Minneapolis and St. Paul campuses.

Now she's collaborating on an experiment to see if a new kind of ultraviolet-reflecting film can ward birds away from these danger zones.

This summer, a research team from the San Diego Zoo installed video cameras and "shock sensors" at three collision-prone buildings at the U, in what it calls its first test of the film in "real-life conditions."

Beard helped point the researchers to what she called "the most deadly areas on campus for bird collisions," including a three-level skyway on the West Bank and Coffey and Ruttan halls on the St. Paul campus.

That's one reason the scientists chose the U for its experiment, according to Paquita Hoeck, who is heading the research for the San Diego Zoo. "I was looking for a site that gets many bird-window collisions and where people had been recording them," she said in an e-mail interview.

The U, it turns out, is something of a magnet for birds because of its proximity to the Mississippi River flyway, a popular migration path for more than 300 species. It's the same reason that activists have been warning about birds colliding with the Minnesota Vikings' new glass-and-steel stadium in Minneapolis.

At the university, migrating birds tend to congregate, like travelers at a rest stop, in the fields of food plants and trees that dot the St. Paul campus. But navigating the nearby buildings has proved hazardous to their health. "The windows at Ruttan Hall are particularly large and dangerous," notes Beard, and the scene of "many fatalities" for Nashville warblers, yellowthroat and white-throated sparrows.

These kinds of bird-glass collisions are "a huge problem worldwide," said Hoeck. Every year, up to a billion birds collide with windows or glass buildings in North America alone, she said. Many die on the spot from head trauma or other injuries; others may recover enough to hop or fly away, but are more likely to fall victim to predators.

The hope, she said, is that the birds might have better luck spotting the glass if it's covered with stripes of UV-reflecting film. For the experiment, the researchers lined some of the windows with a prototype called Anti-Bird Strike film, which was developed by Erickson International with the help of students at the University of Nevada. Other nearby windows were left untreated for comparison.

Now, if a bird crashes into one of the windows, a sensor sends a signal to a video camera to save the footage several seconds before and after the hit, according to Beard. "This way we can verify that it was indeed a bird collision that caused the vibration."

At this point, it's too early to know if the reflecting film is saving any birds' lives, said Hoeck. "We don't have enough data yet to draw conclusions and will have to wait [for] what the spring migration shows," she wrote.

But she does know that some birds continue to collide with the film-treated windows. "So if it makes a difference to the birds at all, it's likely not a very strong one," she said. Still, she's hopeful they'll find a solution eventually.