Chicago Faces Bird Collision Crisis During Fall Migration

During the past fall migration weekend, advocates and volunteers reported that over 1,000 birds were killed or injured after colliding with buildings in the Chicago area. Rescues and recoveries predominantly took place in downtown Chicago and on Northwestern University’s Evanston campus, according to Chicago Bird Collision Monitors.

Expecting north winds on Friday night, volunteers anticipated that many migratory songbirds would fly south to conserve energy for their long journey. On Saturday alone, the DuPage Wildlife Conservation Center received 274 birds from downtown Chicago collisions, and an additional 60 on Sunday. These represented over 20 bird species, including 80 golden-crowned kinglets and 73 brown creepers.

Jennifer Bell, a volunteer, observed birds falling every five seconds, collecting 22 live but injured birds and 40 dead ones. Advocates emphasize the urgent need for preventive measures, specifically through a Bird-Friendly Building Design Ordinance to protect qualifying new buildings in Chicago. Existing buildings can also help by reducing light pollution, which contributes to birds becoming disoriented.

Chicago lies along the Mississippi Flyway, a major migratory route, making it particularly dangerous for millions of birds migrating in spring and fall. According to Cornell University’s Lab of Ornithology, over 5 million birds crossed Cook County on that Friday night. Annette Prince, director of the collision monitors, stressed the importance of the city on migratory routes that birds have used for thousands of years. She advocates keeping Chicago’s architecture bird-friendly to provide a safe passage for them.

In the U.S., it is estimated that a billion birds die each year from crashing into windows. BirdCast data suggests about a billion birds flew over the contiguous states that Friday night. A similar mass collision occurred three years ago in early October, resulting in 960 bird fatalities at McCormick Place Lakeside Center, marking the most recorded in a single event in the country.

Bell noted, “It felt like that on Saturday.” She has rescued 350 birds this fall migration alone through her work with the monitors, indicating widespread issues across 230 square miles of Chicago, which she highlighted is primarily due to glass buildings’ reflective nature deceiving birds.

Volunteers like Allison Sloan in Evanston also rescued injured birds. Doug Stotz from the Field Museum noted the problem is compounded on major migratory nights, making them particularly tragic.

In March, an ordinance was introduced by Ald. Maria Hadden to amend the city’s building code, requiring bird-friendly designs on non-residential and high-rise buildings. Currently in the zoning committee, the ordinance awaits revisions. Robyn Detterline from the Chicago Ornithological Society supports these changes as practical safety measures akin to smoke detectors or sprinkler systems.

Opponents claim such measures would halt development and raise construction costs, but supporters argue the cost is minimal if planned well. Preventive design measures include patterned glass and exterior screens, reducing bird collisions significantly.

For example, McCormick Place’s visible markers resulted in a 95% reduction in bird collisions, with deaths dropping from about 1,000 yearly to 18 in the fall of 2024. Additional bird-safe measures have included closing drapes and turning off non-essential exterior lights.

Since 1995, initiatives like the Lights Out Chicago program have aimed to reduce bird collisions by encouraging buildings to dim lights at night. Annette Prince remarked on the positive impact of this program, noting that dimmed lighting helps protect migrating birds by not attracting them with bright lights.

Prince believes that mandating bird-friendly designs for new constructions and major renovations could inspire existing buildings to adapt as well. “The sooner we do this, the better,” Prince urges, stressing the long-term benefits of reducing bird collisions.