A Simple Window Treatment Drastically Cuts Bird Collisions at a Chicago Landmark

Last autumn, nearly 1,000 birds died in a single night at a single building. This year, after applying simple white markers to the windows, collisions are down by 95% over previous years.

By Susan Cosier

November 20, 2024

Big glass building with white dots on the windows. — The McCormick Place convention center in Chicago has 120,000 square feet of glass surfaces that have killed thousands of migrating birds over the years. A relatively simple solution—applying rows of small white markers to the glass—has helped dead bird recoveries decline by more than 95% compared with previous years. *Photo by Jessica Suarez.*

From the Winter 2025 issue of Living Bird magazine. Subscribe now.

On a warm morning this past October, Dave Willard, the retired bird collections manager for Chicago’s Field Museum of Natural History, walked briskly along a glassy façade on the Lake Michigan shoreline looking for fallen birds. The building made of glass is McCormick Place, the convention center infamous to birders as the place where nearly 1,000 migrating birds met their deaths on Oct. 5, 2023.

The location of McCormick Place along the waterfront of Lake Michigan made it a perennial hazard for migrating birds over the years.

Willard has taken walks like this on nearly every morning during migration seasons for the last 40 years, documenting birds that crash into the building’s windows. He typically collects nearly 1,000 dead birds at McCormick Place over the course of a year, with most mortalities coming during fall migration. This past autumn, however, Willard says he found only 48 dead birds.

The difference appears to be the tiny white circles spaced every two inches along the entirety of McCormick Place’s 120,000 square feet of glassy surface. The markers were applied as part of a $1.2 million project last summer conducted by the Metropolitan Pier and Exposition Authority, which owns and operates McCormick Place, to avoid another avian catastrophe.

“Every migration is different,” Willard says, “but the prognosis is good.”

The markers appear to be doing what they’re intended to do—keep birds from slamming into the glass. On a few heavy migration days in late August and early September, when well over 100 dead birds were collected at the base of skyscrapers across the city by the nonprofit group Chicago Bird Collision Monitors, Willard found only one or two dead birds at McCormick Place. One of the volunteers in Willard’s survey effort even reported seeing a bird fly near the building and veer away as it got closer.

An older man stands in front of a building with small white dots on its windows, and an expansive cloudy sky behind. — Dave Willard, a retired Field Museum ornithologist, stands in front of the remediated windows at McCormick Place. Willard has monitored window strikes at the building since the 1970s. *Photos by Jessica Suarez.*

A corner of a building with white dots on its on its glass, showing how the dots break up the reflection. — Dave Willard, a retired Field Museum ornithologist, stands in front of the remediated windows at McCormick Place. Willard has monitored window strikes at the building since the 1970s. *Photos by Jessica Suarez.*

“If this really works here … then let’s go on to the next worst building, right?” says Willard.

McCormick Place has long had a reputation as one of the worst bird-killing buildings in Chicago. The building’s location right on the lakeshore, in the middle of a migratory pathway, makes it particularly deadly to migrating American Tree Sparrows, juncos, Yellow-rumped Warblers, and dozens of other migratory species that travel through the city by night. (On the night of the 2023 mass collision more than 30 species were killed at McCormick Place alone.)

For several years MPEA has participated in Chicago’s Lights Out program, a voluntary effort to reduce bird strikes by turning lights off during migration, but the convention center only went dark when no staff, visitors, or clients were present. After last October’s disaster, McCormick Place officials drew the curtains inside the convention center to cover up the interior lights during bird migration. The markers are a more permanent solution.

“MPEA has always strived to be a good neighbor and environmental steward, both inside and outside our campus,” said MPEA CEO Larita Clark in a press release. “When we learned of the reported mass collision event last year, we knew that we needed to quickly make additional improvements to protect local and migratory birds as they pass McCormick Place.”

The MPEA worked with Feather Friendly, a Toronto-based company that makes scientifically tested bird-deterrent products for glass, on the project. Installers worked from June to August, carefully transferring the markers from the film to the windows across the entirety of the exterior glassy surface on McCormick Place. Feather Friendly executives now say that other building owners in Chicago are coming to the company to ask about the product that MPEA put on McCormick Place.

“When we first started, it was hard to get anyone to even think about doing something like this,” says Feather Friendly vice president Paul Groleau, who notes that the company sells products for residential buildings as well. “Awareness is at an all-time high.”

That recognition comes not a moment too soon, says Chicago Bird Collision Monitors Director Annette Prince. She notes that the city’s municipal codes currently do not require building owners and designers to make structures bird-friendly, and that a new development planned along the Chicago River—a new Bally’s Casino—includes plans for a massive glass façade.

Prince says that any new buildings in Chicago should incorporate bird-friendly glass from the start.

“Other cities are doing it, and they haven’t collapsed into a pile of dust because they’re being bird friendly,” she says. “I think that we can have attractive architecture and bird safety. They don’t have to be mutually exclusive.”