Our modern love affair with walls of glass is bad news for birds, especially in migratory flyways like the Twin Cities. Architects and homeowners are trying to reduce the carnage.
But soon after he and his wife, Julie Brophy, moved in, they heard a loud thunk. A bird, a white-breasted nuthatch, had crashed into a window and fallen dead on their deck. It was spring -- migration season -- and soon the thunks became an everyday occurrence.
"We'd hear it and cringe," Lutz recalled. "It made us rethink buying the house."
Within a month, 11 different species, some that had migrated from as far as Central America, had crashed and died at the couple's home. "We had to do something," Brophy said. So Lutz crafted a solution, using screening and clear decals, that has reduced their bird casualties to virtually zero.
"It's not pretty, but it's been 100 percent effective," Brophy said.
Retrofitting their home to eliminate feathered fatalities has worked for Brophy and Lutz. But a growing chorus of bird enthusiasts are advocating avian-friendly architecture at the design stage as the best prevention. It's a national movement that started in Chicago and has spread to other major cities, including the Twin Cities.
Big expanses of glass are generally bad news for birds because they reflect sky, water and habitat, attracting flying species until it's too late for them to put on the brakes. Window collisions kill at least 100 million and as many as 1 billion birds in the United States every year, according to Laura Erickson, the Duluth-based author of "101 Ways to Help Birds."
"Most people do not want to kill birds," Erickson said. But many homeowners and design professionals perceive -- incorrectly, she said -- that it will cost a lot or be "grossly inconvenient" to design kinder, gentler structures.
"You can build a bird-safe building without any additional cost," said Joanna Eckles, coordinator of Project BirdSafe/Lights Out for Audubon Minnesota. "There are so many solutions," including types of glass and how they're used. Educating people about those solutions is the goal of Project BirdSafe, which last year published its Bird-Safe Building Guidelines (mn.audubon.org).
The issue is critical in the Twin Cities because of its location on the Mississippi River, according to Eckles. "We're on a major migration route, a key stopover site for migrating birds."
And our current love affair with floor-to-ceiling glass has increased the hazards for migrating birds, Eckles said. "I love glass, too. I'd love to live in a glass box, but knowing what I do has polluted my vision."
Ironically, sustainable building practices, such as using the sun to light and heat structures, and incorporating nature-friendly landscapes, also are putting birds at increased risk.
"It's a paradox," said architect Edward Heinen, Edward Heinen Architectural Consulting, Burnsville, who helped draft Audubon Minnesota's bird-safe building guidelines. "We're restoring habitat with native plantings and rain gardens, so we're attracting birds to the site, but the glazing can be hazardous."
Heinen got interested in bird safety while working in Chicago, another migratory hub. At an Earth Day event at the Field Museum, he saw a display of birds that had died crashing into one glass building. "There were warblers, woodpeckers, hawks, even a couple of bald eagles. I thought, 'Here's our nation's symbol, crashing into glass.'"
When Heinen moved to Minnesota several years ago, he got involved in "monitoring" [collecting data on bird-window collisions], which led to collaborating on the bird-safe building guidelines and developing a lecture series for design professionals.
Architects don't have to give up glass to make buildings safer for birds, Heinen said. "There are ways to treat the glazing to improve poor birdy's chances."
Birds and books
The downtown Minneapolis Central Library, completed in 2006, is a good example of a building that utilizes a lot of glass but is still bird-friendly, he said.
Bird safety was not the driving force behind the design but it was "part of the dialogue," said Tom Hysell, a principal with Architectural Alliance, the Minneapolis-based architect of record for the Pelli Clarke Pelli-designed project.
The insulated glass has a silk-screened pattern -- called a frit or fritting -- that reduces solar glare and helps birds identify it as a solid object. The patterns in the glass represent "distinctly Minnesota" images: water, snow, birch trees and prairie grass, abstracted from photographs, Hysell said.
Glass at the library also is angled slightly, so it reflects more of the ground below and less of the sky above.
Manufacturers are starting to develop other bird-friendly solutions. One glass product, Ornilux, has an ultraviolet striped pattern on the inside to increase visibility for the birds while appearing relatively unobtrusive to people.
Bird-safe building criteria are in the process of being incorporated into Minnesota's Sustainable Building Guidelines, Eckles said. (New York, Toronto, Chicago and San Francisco have already adopted standards for bird-safe buildings.)
In addition, bird enthusiasts are working to get a dedicated credit for bird safety under LEED (Leadership in Energy and Environmental Design) guidelines. Currently, bird-friendly projects can earn a credit under "Innovation," but not a separate credit, Heinen said; adding a bird-safety credit would encourage bird-safe features and give projects a way to earn more LEED points.
In the meantime, homeowners like Lutz and Brophy are doing what they can to protect airborne visitors.
Lutz's homemade screens, fitted into frames that cover their biggest windows, have added a few hours to his chores because he has to take them down twice a year to wash the windows. But it's worth it, he said, to prevent birds crashing and dying on a daily basis. The screens not only cut the reflection, but also act as a trampoline for the few birds that do fly into it.
"A lot of people are doing these Rube Goldberg attempts like we do," he said. "It doesn't look perfect, but we'll live with this until they come up with something better."
Kim Palmer • 612-673-4784