Time is of the essence to reduce injuries and fatalities to the feathered friends in the area of the Minnesota Vikings' new stadium, which is more than half-way built.
Christine Sheppard, the bird collisions campaign manager for the American Bird Conservancy (ABC) in The Plains, Va., said warblers, thrushes and sparrows typically are the most frequent victims.
“We discovered in our tests with tunnels that what birds think they can fly through is based on their body size,” Sheppard said. “These little warblers with their wings stretched are maybe 6-inches wide. If you've got lines spaced 4 inches apart most of these birds will think ‘damn I don't want to hit my wings so I'll go around.'”
Window film with horizontal lines that are 2 inches apart would be even better on the 8,500 glass units comprising the stadium exterior and five huge entranceways expected to be the world's largest pivoting doors, Sheppard added. But she acknowledges that developing a new material is a tremendous undertaking.
“It's not trivial at all, especially an outside window film because you have to make it capable of withstanding constant bombardment with UV radiation whether it's visible in the human range or not,” she said. “There are a lot of things to be resolved for this to happen. If 3M is looking at this they're not going to come up with a solution before the stadium is built. That's for sure. And, unless someone is willing to donate the money to put said window film up, we might be back where we started — but I can't speak for the Vikings.”
There is a clear Solyx polyester film on the market from Decorative Films LLC of Frederick, Md., that has very narrow horizontal lines and deters bird collisions, Sheppard said. It has an expected useful life of seven years and been applied to the exterior of office windows and zoo exhibits. The product was used on a large glass wall of the bear enclosure at the Philadelphia Zoo to protect birds and prevent visitors young and old from encountering winged victims.
“It's not very obtrusive and it seems to be highly effective at stopping collisions,” Sheppard said. “We got this window film up and the zoo hasn't had a single collision since and the most important thing is that they haven't had a single complaint from the public that they couldn't see the bears. This is important because any solution has to work for both people and birds.”
