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Chicago Is The Deadliest City For Migratory Birds: What Can CRE Do About It?

Annette Price and a score of volunteers spend many of their mornings scooping up the many dead or injured birds that struck one of Chicago’s downtown towers overnight. They document each find and send the survivors, thousands each year, to a recovery center in the suburbs.

Annette Price and a rescued northern flicker

The tiny bodies, mostly small migratory birds weighing just a couple of ounces, are especially prevalent in the autumn, when millions migrate from northern latitudes along the lakefront down to Mexico and Central America, and in the springtime when they return home.

The group, called Chicago Bird Collision Monitor, started with a handful of volunteers in 2003, Price said, and now has about 130 people who walk the streets just after sunrise and aim to raise awareness of the problem.

“We pick up about 5,000 birds every year, but we can’t get to every one that’s lying on every corner, or that is lying on the roof of a building, and by 8 or 9 o’clock, the rest get swept up, so few people really know what is happening,” she said.

The group has made inroads in Chicago’s commercial real estate community, getting many downtown building owners to participate in a voluntary program that protects migratory birds by dimming or turning off many skyscraper lights during migrations.

But owners and developers may need to pay even closer attention. Chicago is the deadliest city in the country for migratory birds, according to a Cornell study, and bird advocates like CBCM have gotten city council members to sponsor legislation that would mandate the use of bird-friendly technology and materials in many new and existing buildings.

Similar legislation is working its way through other city councils, state legislatures and Congress, and with more people growing alarmed about buildings' impacts on the environment and wildlife, tenants increasingly favor buildings judged environmentally friendly.

“When we started doing this, people would see us with our nets, and ask if we were trying to catch butterflies, but now people always seem to know what we’re doing, and understand its importance,” Price said.

Douglas Stotz, senior conservation ecologist with the Keller Science Action Center at Chicago’s Field Museum, said downtown Chicago lies directly in the migratory path of many birds. The city’s skyscrapers act as light beacons, drawing thousands into deadly collisions.

“Birds are drawn to the lakefront as dawn nears, and they come streaming in to find places to spend the day,” he said.

Not all modern structures are death traps. Stotz said ornithologists consider Chicago’s Aon Center a perfect building. Its mostly marble-clad exterior and narrow windows attract few birds, who fly around it in safety, but most modern skyscrapers use vast glass facades. These confuse birds, which frequently mistake reflections of trees or the sky as objects they can fly into.

Recent technological advances may also have increased bird strikes and deaths, according to Justin Illg, design technical director of Wight & Co., a Darien, Illinois-based design firm.

In the 1990s, a new window coating called Low E was introduced that allows visible light to flow through glass, while blocking solar heat and ultraviolet rays. That boosts energy-efficiency, but also increases reflectivity, making it more likely birds will hit such glass.

“There were a lot fewer bird strikes in the '70s and '80s because glass was not as reflective,” Illg said.

In the 1990s, Chicago conservationists and wildlife advocates joined with property managers from across downtown to create Lights Out Chicago, a program that encourages building managers to turn down lighting during the migratory seasons.

Price considers the program a remarkable success, as most downtown building managers eventually agreed to participate, and Stotz believes it is the easiest method to reduce bird deaths.

“It’s not realistic to tell building owners they need to replace all of their glass, but we can ask them to turn down the lights,” he said.

Stotz considers decorative lighting especially hazardous for birds, and just turning these down or off can make a big difference. He points to 311 South Wacker, a 65-story skyscraper completed in 1990, as one that had been particularly worrisome, partly due to a decorative crown that can be seen for many miles at night.    

But its owners agreed to take part in Lights Out Chicago, he said, and that has reduced the number of bird deaths.

Cirrus Tower at Lakeshore East

Tabulating precisely how many birds are saved at a particular location, or how many are killed throughout the city each year, is extremely difficult, Stotz said. Many bird carcasses fall into inaccessible areas, or get swept away by custodial staff before the deaths can be recorded.

Furthermore, the stream of migratory birds, which involves hundreds of species, is extremely complex and ever-changing, so it is impossible to predict where, when or if birds will strike a building on a given night or even over a season.

The Field Museum has studied bird mortality at McCormick Place, the landmark convention center on the South Side’s lakefront, for more than 40 years, Stotz said. More than 160 species have hit McCormick Place and died over these years, including many warblers, and migratory sparrows, such as song sparrows and white tails. But in the 1990s, McCormick Place managers began masking the interior lights with curtains, and seasonal bird deaths recorded dropped about 75%.

Although the complex developed a reputation as a deadly place for migratory birds, Stotz said that is only because researchers have devoted so much time to studying the phenomenon there, and the solution adopted shows just how much progress can be made at other buildings.

“I don’t think there is any reason to believe McCormick Place is special,” he said.

Stotz said he hopes the owners of every tall building along the lakefront, even ones that haven’t noted any bird strikes, take part in Lights Out Chicago.  

Price hopes every building that notices a large number of bird deaths will report it to her group, and said they will work with anyone to come up with cost-effective solutions.

“It’s not about naming and shaming buildings, we know no one wants to kill birds.”

Lakefront And Legislation Front And Center In Bird Safety

Stotz believes the city’s shoreline has become even more important to the health of the continent’s bird population. The city largely preserved Daniel Burnham’s century-old vision for an open, green lakefront, but in the 21st century park officials began replacing long stretches of close-cropped lawns with migratory bird habitats, which include naturally occurring prairie grasses.

“The lakefront parks are hugely important for migratory birds,” Stotz said.

But that may also have increased the dangers. Migrating birds settle down each morning into whatever green space they can find, increasing the possibility of deadly collisions with the lower levels of nearby lakefront buildings, so a lot more is needed than simply turning down the lights.

That is where the new legislation before the Chicago City Council comes in, Price said.

CBCM and other conservationists recently formed Bird Friendly Chicago, an advocacy group, and got 2nd Ward Alderman Brian Hopkins to sponsor an ordinance, introduced earlier this year, that would mandate design elements that would reduce bird mortality in new construction, as well as buildings undergoing renovations that require a permit, especially on lower levels, where many collisions occur.

Price considers the legislation a modest step, and the high participation rate in Lights Out Chicago gives her hope it will garner the necessary support to become law.

But many in the commercial real estate community still have questions.

“We still remain in the dark about how much this would cost,” BOMA/Chicago Director of Government Affairs Ron Tabaczynski said.

Above all, his group is confused about which buildings would have to meet the new standards. The legislation calls for the inclusion of any building needing a renovation permit.

“That’s basically everything, so if someone does a minor lobby renovation, does that trigger the ordinance?” he asked. “We don’t believe that’s the intent.”

BOMA officials, who have spoken with Hopkins about their concerns, also worry that attempts to meet LEED standards with more efficient glass will run afoul of legislative attempts to protect wildlife.

“This is not a knee-jerk response, but we need to get a better handle on what we’re being asked to do,” Tabaczynski said.

Migratory birds collected by The Field Museum

The legislation did not make it out of committee, and a spokesman from Hopkins’ office said they are evaluating the critiques, and plan to flesh out the proposal with more details and will soon bring it back before the council.

Wight’s Illg believes that regardless of whatever legislation appears, many in the commercial real estate industry are becoming more aware of bird mortality, and the role skyscrapers play. But there are some gaps in awareness.

“It is definitely recognized as an issue, but mainly by building owners, and not as much by building users, who are less likely to be aware it’s a chronic, escalating issue.”

Addressing the problem involves tough choices.

Developers can decide to use fritted glass, which include ceramic patterns or grids baked into the surfaces, which alert birds that a solid object is in the way, Illg said. That can be costly, especially for buildings with mostly glass exteriors.

Wight did use fritted glass for a portion of the new 10-story Will County Courthouse in Joliet. Even though that was mostly to give a bit of privacy to jury rooms, it will also protect birds flying around the glass-walled building’s lower levels.

Other developers have likewise found some design choices made for functional or aesthetic reasons can also reduce bird mortality.

Lendlease officials knew protecting migratory birds would be important when developing Cirrus, a 47-story luxury condominium tower now rising at 211 North Harbor Drive along Chicago’s lakefront in the Lakeshore East community, along with Cascade, an adjacent 37-story rental tower.

“We’ve been dealing with [the] issue since the day we started this project,” bKL Architecture founding principal and project designer Thomas Kerwin said.

He first saw a report from the American Bird Conservancy on bird-friendly design three years ago, and sent its experts renderings of the proposed buildings at Lakeshore East, and found some design elements meant to increase its visual appeal will also protect wildlife.

“We reached out to get their opinion, and the great news was that this building was great for birds as well,” Lendlease Creative Design Director Linda Kozloski said.

Instead of sides of sheer glass, Cirrus and Cascade will have serrated walls, which will cast shadows as the sun moves around the buildings, increasing visibility to birds and reducing daytime strikes, Kerwin said.

Building owners can retrofit existing structures by coating windows with visual cues for birds, but that strategy is most effective on exteriors.

“That means you’ve got to pay someone to scale your building and apply it, plus at some point the coating will start peeling and bubbling and will need reapplication, so that’s also expensive,” Illg said.    

Kerwin is also skeptical.

“You can certainly put a lot of money into using specialized glass, but I don’t know if it’s feasible to use across a building with a 60-story facade.”

The use of frit technology also presents difficulties, especially for residential buildings like Cirrus and Cascade.

“A lot of these buildings depend on their views, but it would be much easier to do in the first 36 feet,” he said.

Lendlease will include a nearly 1-acre park adjacent to its new residential towers, most likely increasing both the spot’s attractiveness to migrating birds, and the importance of making sure there are protections at the lower levels.

“What we’re trying to do at Lakeshore East is to bring back nature, so we want to make it the safest place that we can,” Kozloski said.

“For me as an architect, up until three years ago, this was not even an issue, but I’ve learned a lot, so it now informs everything we do,” Kerwin said.     

Illg’s firm is looking to solve this problem at its own suburban headquarters. Although only a small portion of the two-story building’s exterior is glass, employees still sometimes find dead birds outside below the windows. Wight hasn’t decided yet on how to change the windows to increase bird safety, but anticipates using the eventual solution to educate clients.  

“We do want to reckon with it, and hopefully, turn our building into a test laboratory that’s ready for the next spring migration,” he said.

Price is heartened by all these efforts. She works full time in public schools as a speech pathologist, and has loved both birds and architecture since arriving in Chicago to attend Northwestern University in the 1970s.

“I was dismayed to find out such a beautiful skyline was so deadly. When we find these birds we know it's not a pretty death, so many die of massive internal hemorrhaging. But this is something I can do.”