Saving Milwaukee’s Birds, One Window at a Time

Up to a billion birds in the United States each year die from collisions with glass, reports the American Bird Conservancy. Scientists at UW-Milwaukee are working to lower that number.

When the Milwaukee Bucks announced last month that their new home was the nation’s first sports arena made collision-safe for birds, it pointed up a much bigger problem.

Up to a billion birds in the United States each year die from collisions with glass, reports the American Bird Conservancy, and though the Fiserv Forum is designed to combat that grim statistic, there are many glass buildings in Milwaukee that are not so bird-friendly.

Scientists at UW-Milwaukee are working to help improve that situation.

UWM’s Institute for Ecological Design emphasizes the need for sustainability, and Glen Fredlund and Filip Tejchman are addressing this issue by taking on the task of determining how to lessen and prevent birds from colliding with glass. Fredlund is with the university’s geography department, and Tejchman the school of architecture. Their ultimate goal is to add retrofits to the windows of existing buildings, but before that, Fredlund and Tejchman are developing programs that would allow them to better study bird strikes.

It was Fredlund’s work on documenting and measuring the issue of bird strikes at UWM that encouraged later efforts. His “Dead Bird Project,” sponsored by UWM, consisted of observing various buildings on campus in order to detect areas that are the most at risk of collision. The ultimate goal of this project was to compile all of the data together into an app that will predict where on buildings bird strikes are most likely to occur.

Tejchman is currently assisting with the development of a “low-cost autonomous monitoring system for tracking bird collisions.” In the past, bird strikes have been monitored by volunteers, but Tejchman says that system was ineffective. For example, birds’ carcasses might have been transported to another location by a predator, the bird could have survived the initial impact before flying somewhere else to die and volunteers can’t always determine which side of a building the bird had struck.

This new monitoring system, called BirdCALL, logs the date and time of every bird strike and uses sensors that allow it to pinpoint the specific window or area on the building that the bird collided with. This would allow, Tejchman explains, for people working on this project to determine where to place retrofits.

Fredlund and Tejchman’s work dovetails with that of Fiserv Forum’s designers. That building was constructed with bird safety in mind and therefore does not require retrofits. Rather, the windows on the arena incorporate fritting, a thin ceramic layer on the glass that creates tiny lines. Fritting reduces the transparency of the glass for birds, which signals to them that the glass is a barrier and not something they can fly through.

Not being able to see glass is the reason so many birds fly into it. Many windows reflect the surrounding vegetation and landscape, and birds don’t perceive the window as a barrier. Plants and greenery inside buildings can also confuse birds, as well as glass corners and narrow passages that allow the bird to see habitat on the other side.

William Mueller of the Western Great Lakes Bird and Bat Observatory (WGLBBO) reports that “North American cities in general have a big problem with bird collisions,” but Milwaukee can prove especially problematic.

Milwaukee is located directly in the flight path of migrating birds whose flyway is parallel to Lake Michigan. “Data from various studies shows spikes during migratory periods,” Mueller says. He adds that in an average year in Wisconsin, about 350 species of birds come into the state, but of those, only 220 stay here to breed. That means that over 100 species of birds migrate out of state and use flyways like the one found along Lake Michigan.

Mueller says migration takes place during most of the year – northwards from late February to early June and southwards from July to the end of November. Given the number of species that migrate in Wisconsin and the location of Milwaukee, this implies that Milwaukee can prove to be significantly more dangerous for bird strikes than the average U.S. city, which is why retrofits would make such a big difference.

However, adding retrofits to existing buildings isn’t necessarily enough, especially given that roughly half of bird collisions occur on home windows.

So what can you do to help? Mueller says that the biggest issue is reflection, so putting up lots of decals, anti-reflective tape, or other window obstructions that make it clear to birds that the window is a barrier help a lot. At WGLBBO’s building, he said, they put up anti-reflective tape in a vertical pattern about six to seven inches apart and found that this decreased the mortality rate of birds by 98 percent. Acts like these are both simple and effective.

Mueller regards the Fiserv Forum highly in light of its inclusion of bird-friendly glass, and is excited to see what will come next. “It kind of sets the tone for other cities and shows what’s possible,” he says.