When Ald. Ledell Zellers saw designs for a proposed 11-story office building slated for the 900 block of East Washington, she loved them, she said. But she had one major concern with the plans, which included an all-glass tower.
She told Curt Brink, the developer of the project: “I would like to be able to support it. Are you going to do bird resistant glass?”
Asking about how proposed buildings will affect birds is becoming more common, said Aaron Williams, assistant campus planner and zoning coordinator for Campus Planning & Landscape Architecture at the University of Wisconsin-Madison. Along with “Where are you putting the bicycles? Where are you putting water fountains?” comes “What are you doing to mitigate bird strikes?”
Glass can be dangerous for birds, as they sometimes fly into windows, stunning, injuring or killing themselves. And individuals around Madison are joining in on a nationwide movement to help prevent building collision deaths.
“When you look at a tall, glass-fronted building, what do you see?” the Madison Audubon Society website reads. “If you put on a ‘bird-lens’, you would quite likely see more open sky to fly through, more habitat to tuck into, or more moonlight to guide you on your journey. The result is thousands of birds crashing into windows.”
“The problem is basically that birds don’t recognize glass as a barrier,” said Peter Cannon, and that leads to two problems: birds see through the building or see a reflection on the glass, and think they can fly through it.
Cannon was active in the Madison Audubon Society for many years and served on the National Audubon Society Board for seven years.
Everyone knows that birds occasionally fly into glass, and have likely found a stunned, injured or killed bird in their backyard, Cannon said. But in the early 2000s, awareness of the prevalence of the issue “was close to zero,” even among bird lovers like himself.
“One or two birds in your backyard, you don't really think about until you start multiplying by the number of houses in the United States,” Cannon said.
In a 2015 report, the American Bird Conservancy estimated that glass kills somewhere between 100 million to 1 billion birds annually in the United States.
As all-glass curtain walls came on the scene, they brought a “general increase in the amount of glass used in construction,” ABC’s report said. And generally speaking, the more glass in a building, the more likely it will be dangerous to birds.
The report added that even for those not interested in bird watching, birds bring plenty of practical benefits. They pollinate plants, spread seeds and eat insects.
With rising awareness of the problem has come innovative ideas on how to address it. Developers can create buildings with glass that lessen the hazard for birds, using measures like glass treatments, patterned or frosted glass, screens, latticework, netting, shutters and exterior shades.
The installation of patterned glass panels on a shiny New York convention center known as “one of the deadliest buildings for birds in New York City” decreased bird deaths by 90 percent, the New York Times reported.
While bird-resistant glass can be a “greater expense,” Zellers said, “like anything, if the market starts demanding it,” prices will drop.
Williams said it’s somewhat analogous to Americans with Disability Act building requirements. Developers didn’t use to install handrails or slope sidewalks, but “now it’s just a common thing.”
“As long as it’s designed from the get-go, it should not be a budget breaker by any means,” Williams said.
Illustrating this point nicely is a tale of two stadiums. The new Milwaukee Bucks arena was proclaimed the “world’s first bird-friendly sports and entertainment venue,” and one architect for the project called the costs to make it bird-safe “inconsequential.”
But a few years ago, the potential for bird deaths raised concerns when the Minnesota Vikings' U.S. Bank Stadium was proposed with thousands upon thousands of square feet of glass. One architect called it a “fatal avian collision trap,” and advocates said the cost of bird-safe glass would add $1 million. The Minnesota Sports Facilities Authority said switching to bird-safe glass would cost an extra $60 million.
After the stadium was built, the Audubon Society came out with a report detailing 60 dead birds they observed over a few months, and has since said retrofitting the glass to make it friendly for birds would cost “an estimated $10 million — $9 million more than installing it in the first place.”
Zellers became an advocate for bird-safe buildings after being made aware of the issue four years ago by Cannon, her constituent. While there are many factors that impact bird deaths, Madison can actually do something about bird collisions with glass windows, Zellers said.
On Friday, asked about any measures to mitigate bird strikes on the proposed office building, Matt Brink, Curt Brink’s son, said “we are still working through the options available and determining feasibility.” Zellers also voiced her concerns with the plans for massive glass towers in the Judge Doyle Square project.
The UW-Madison is also attempting to address the problem on campus. A few years ago, Williams was at a meeting discussing now underway reconstruction of the Southeast Recreational Facility (to be known as “the Nick”), when the architect was asked “What are you doing to mitigate bird strikes?”
Neither Williams nor the architect knew how to answer the question, and that was a “lightbulb” moment, Williams said, where he realized “we need to think about what should happen here.”
Now Williams is involved with Bird Collision Corps, a partnership between the UW-Madison Department of Forest and Wildlife Ecology, Department of Facilities Planning and Management, and the Madison Audubon Society.
With the help of volunteers, the corps monitored about a dozen buildings to look for stunned or dead birds on the ground and identify the campus buildings that were the biggest problem. Bird mortalities tend to be higher during migration periods, so UW did the study in the spring and fall of 2018, said Anna Pidgeon, associate professor in the UW-Madison’s Department of Forest and Wildlife Ecology.
Some of the biggest building offenders: the Microbial Sciences Building, which “has this big bank of windows and an open area of vegetation in front of it” on its east side, Pidgeon said. They found a glass walkway at Ogg Hall is another big contributor to bird strikes, as is the Kohl Center with its glass-heavy entrance.
Now the project is trying to get funding to continue the project by adding stickers or film to the glass of a building and then monitoring to see if that has any impact on bird collisions, Williams said. And on the front end, campus planning is working to design bird-friendly buildings. A planned Linden Drive parking garage, will have patterns on the glass stair towers, and the university switched the many-windowed design for the Nick to a less translucent glass, Williams said.
Williams pointed out that windows in residential houses also contribute significantly to bird mortalities. Screens can go a long way to cut down on collisions, Cannon said. Pidgeon said homeowners can retrofit their windows and turn off interior lights at night, particularly during peak migration season.
Many birds migrate at night by the light of the moon, Cannon said, so “the lights confuse them and turning out the lights on a big building, whether it’s glass or not, makes it easier for the birds to avoid it.”