In New York City, a hidden crisis unfolds each spring and fall as thousands of birds on migration paths collide with the city’s glass-covered buildings. Brightly colored travelers such as warblers and woodpeckers face an untimely end when they fly into the reflective surfaces of buildings like Circa Central Park, a condominium complex near Central Park’s northwest corner (NYC Bird Alliance). These collisions are not isolated incidents but are part of a much larger, often devastating pattern affecting North America’s migratory bird populations.
Figure 1
Twenty-Eight Birds Found Dead After Flying Into Circa Central Park

Note. From Deathtrap NYC Condo Killed 28 Birds in One Day: Advocates, by Lapin et al., 2020, New York Post (https://nypost.com/2020/05/18/nonprofit-slams-upper-west-side-condo-for-killing-migratory-birds/).
Glass poses a particular danger to birds, as it reflects the sky and surrounding trees in ways that birds cannot perceive. Many migratory birds, accustomed to forests and open landscapes, observe these reflections as real and fly directly into them. As Dustin Partridge from NYC Audubon explains, the expanses of reflective glass in buildings like Circa have created tragic hotspots for bird collisions (New York Times, 2023). This issue is magnified in dense urban areas where the prevalence of glass structures and artificial lighting during migration seasons create particularly hazardous conditions.
The number of birds killed by building collisions each year in the United States reaches into the hundreds of millions. In New York, species like the white-throated sparrow and various warblers are disproportionately affected. The catastrophic loss of these migratory birds contributes to the overall 30 percent decline in North American bird populations since 1970 (New York Times, 2023). This decline is not due solely to collisions, as habitat loss and climate change compound the problem. However, the significant loss of life from glass collisions is an especially preventable cause.
Figure 2
White-Throated Sparrow

Note. From White-Throated Sparrow (Zonotrichia Albicollis), by Minardi, R., 2022, NYC Bird Alliance (https://nycbirdalliance.org/blog/white-throated-sparrow-zontrichia-albicollis).
Because it’s one of New York’s deadliest sites for birds, Circa Central Park’s building has gained much negative attention. Its unfortunate reputation as a “death trap” for birds has spurred both local outrage and an internal call for change. Many residents, driven by distress at the continual bird deaths, have rallied to implement bird-friendly solutions; their efforts include adding dot-patterned window films, which reduce reflectivity and make the glass visible to birds without greatly interfering with the views that draw people to live there. The first phase of this project, focused on the building’s courtyard, has cost around $60,000, signaling a substantial investment from residents toward mitigating bird deaths (New York Times, 2023).
This response at Circa is part of a larger trend. Conservation groups like NYC Audubon have collaborated with volunteers and citizens to patrol buildings, documenting bird casualties and advocating for citywide legislative changes. In cities nationwide, volunteers like Melissa Breyer of Project Safe Flight collect data, report findings, and push for awareness and prevention. “My most emotionally overwhelming day happened there on September 14, 2021,” she said. “It was a mass casualty. I found 270 carcasses at three buildings—all within 90 minutes. Guards and passersby were helping me, dropping birds in my lap” (NYC Bird Alliance, 2022). This basic effort is a key driver of the bird-friendly building standards now required for new constructions and major renovations in cities like New York and San Francisco.
Preventing bird collisions requires cooperation between architects, building owners, and residents. Cities across North America are introducing policies to support bird-friendly design, encouraging innovations like patterned or frosted glass, especially on buildings’ lower levels where most strikes occur. New York’s Javits Center, for instance, saw a 90 percent drop in bird collisions after its glass was redesigned with bird-safety features (NYC Bird Alliance).
Figure 3
The Dotted-Pattern Bird-Friendly Glass Used By The Javits Center

Note. By Javits Center, 2020, X (https://x.com/javitscenter/status/1214655285547155456).
For older buildings, retrofitting windows can be challenging, both financially and aesthetically. Yet, companies like Feather Friendly have seen rising demand for their bird-safe window treatments, suggesting a shift in attitudes among property owners (New York Times, 2023). NYC Audubon and similar organizations have found that public awareness is steadily transforming consumer expectations. People increasingly view bird-safe buildings as a desirable standard, and even a marketing advantage for real estate, as awareness of environmental issues continues to grow.
While New York has made progress, existing buildings remain a difficult hurdle for widespread implementation of bird-friendly standards. At Circa, although many residents support bird-safe retrofitting, some remain concerned about the impact on their views, especially those facing Central Park. The property board’s decision to move forward gradually—testing initial changes in the less scenic courtyard first—exemplifies the compromises and negotiations that often characterize retrofitting projects.
Figure 4
Circa Central Park’s Landscaped Courtyard

Note. From Amenities, Circa Central Park (https://www.thecircacentralpark.com/amenities).
However, the costs of inaction may ultimately be more compelling. Bird fatalities, well-documented and shared widely on social media, are beginning to influence building marketability. Some residents and architects argue that a building’s reputation as a “bird killer” can lower its appeal to environmentally conscious buyers or tenants.
The issue of bird collisions in New York City sheds light on the need for innovative, ethical urban design that accommodates both human and wildlife needs. From Circa Central Park to the World Trade Center, community-driven conservation efforts demonstrate a willingness to confront and mitigate the risks posed to migratory birds. The continuing shift towards bird-safe architecture signals hope that these collective efforts can reduce the tragic toll on bird populations.
References
Amenities (n.d.). Circa Central Park. https://www.thecircacentralpark.com/amenitiesCollision Monitoring
(n.d.). NYC Bird Alliance. https://nycbirdalliance.org/our-work/conservation/project-safe-flight/collision-monitoring
Einhorn, C. (2023). This N.Y.C. Building Is in the Bird-Killing Hall of Shame. It Wants Out. New York Times. https://www.nytimes.com/2023/10/16/climate/new-york-birds-windows.html
Javits Center (2020). X. https://x.com/javitscenter/status/1214655285547155456
Lapin, T., Mongelli, L., Musumeci, N. (2020). Deathtrap NYC condo killed 28 birds in one day: advocates. New York Post. https://nypost.com/2020/05/18/nonprofit-slams-upper-west-side-condo-for-killing-migratory-birds/
Minardi, R. (2022). White-Throated Sparrow (Zonotrichia Albicollis). NYC Bird Alliance. https://nycbirdalliance.org/blog/white-throated-sparrow-zontrichia-albicollis
Robins, C. P. (2022). Introducing the Volunteers of Project Safe Flight. NYC Bird Alliance. https://www.nycbirdalliance.org/blog/introducing-the-volunteers-of-project-safe-flight