Glass sound barrier proves fatal for flock of Swedish birds

Eighty birds flew into a glass sound barrier in western Sweden on Sunday, in a mishap that proved fatal for the vast majority of the flock. "It was awful and tragic," Kirsten Ekholm of the Bird Center in Partille said. "It's sad because it's so unnecessary. We know how to avoid this." Ekholm was at the Bird Center, an organization near Gothenburg which rehabilitates injured wild birds, when a couple came in with several shaken Bohemian Waxwings. Ekholm accompanied them back to a glass sound barrier near a highway, where she was shocked to see nearly eighty bird bodies strewn about.

"We have never seen so many at one time," Ekholm recounted. "And most of them were very young birds. It was a terrible sight." Ekholm spent her Sunday gathering the bodies and examining the dead. Seventy-two of the birds were already dead when she arrived, and one died of its injuries during the night. Seven were still alive on Monday morning, but she said there was no guarantee they would make it. "It's difficult to say if they will live. Many of them have internal bleeding, and one had its eye completely smashed," Ekholm said. Bohemian Waxwings, which are common in the northern parts of Sweden, Finland, and Russia, desert their nests in the winter to seek berries further south.

This flock landed in a group of trees near the sound barrier to enjoy rowan berries, one of the species' favorite foods, and then proceeded to fly straight into the glass wall separating a bike path from a highway. "This is nothing new," said Ekholm. "We’ve known about this for years. Birds can’t see the glass and fly to their deaths. And if you build glass walls and then plant fruit trees there, you’re just luring them to a deathtrap." Tommy Järås, who runs the Bird Center in Partille, agrees. "It’s a massive problem," Järås said. "This many at a time is unusual, but birds fly into glass every day. We’re talking about millions of birds in Sweden every year."

If cities must build with glass, Ekholm said, there are ways to make it less fatal for birds. Glass walls can be patterned, featuring squares or lines that discourage birds from flying into them. Otherwise cities can simply use other materials. "It can’t be the most economical or environmentally-friendly choice to build with glass," she mused. "It’s expensive and often needs to be cooled in summer and heated in winter. People just think it’s prettier." But aesthetics take a toll, and the price is high. "This glass wall runs along a bike path, and there have been so many dead birds there that no wants to bike there anymore," Ekholm remarked. "So is it in even worth it to build with glass? It’s a question of if the public really wants this."