New York City’s skyscrapers light up every night’s sky, creating a magnificent view of modern architecture. However, beneath the facade lies a dreadful reality: millions of migratory birds die each year as they collide with the city’s tall structures. The problem has escalated so far that this is now recognized as a pressing conservation issue, driven by many factors that are difficult to deal with in a city of NYC’s size. These tragic incidents not only impact the bird populations but also reflect the overlooked environmental consequences of urbanization.

The number of birds’ deaths in New York City is shocking. During migration seasons, hundreds of millions of birds pass through the area, often disoriented by the city’s dazzling lights and glass exteriors. According to a well-known study carried out by the New York City Audubon regarding the issue, up to 230,000 birds fatally lose their lives each year in the city alone as a result of the impacts of window collisions. Light pollution, which severely gravitates the problem, combined with architectural designs, creates a deadly combination. Birds are drawn to illuminated structures, especially during their nocturnal migrations, when they rely on celestial cues to navigate their route. When artificial lights disrupt this process, birds frequently fly towards these bright structures, colliding with windows or tiring themselves by circling the lights until they succumb to exhaustion.

Figure 1.

Breyer, M. (2021). Blackburnian Warbler found in downtown New York City. Audubon Magazine. https://www.audubon.org/news/a-video-captures-dreadful-toll-window-strikes-take-migrating-birds

Highly reflective surfaces also aggravate the situation because birds cannot distinguish between reflections and actual spaces. A bird may perceive a mirrored window as an open sky or a grove of trees, encouraging it to fly directly into the structure. Despite efforts to reduce such collisions through building design and light management, buildings such as the World Trade Center and the Javits Center have become notorious for bird death (American Bird Conservancy, 2021). Beyond the heartbreaking loss of individual lives, these crashes pose a greater harm to bird populations by increasing mortality rates across species.

Figure 2.

Jeffrey, J. (2024). After surviving building collisions, around 60 per cent of birds die in rehabilitation care. New Scientist. https://www.newscientist.com/article/2442907-bird-deaths-from-building-strikes-may-be-double-past-estimates/

Another contributing factor is the lighting used in New York City. White and blue lights, which are often utilized in metropolitan areas, are especially appealing to birds. According to studies, these lights interfere more with birds’ migratory pathways than red or amber lights. The lights not only interfere with their navigation but also lure them to regions they would normally avoid (Loss et al., 2014). We have to keep in mind that many birds migrating through New York are already under threat in their natural habitats, including habitat loss and climate change. For some species, urban fatalities may bring them closer to extinction.

Figure 3.

Nagle, M. (2019). One World Trade Center (WTC) stands in the lower Manhattan skyline as birds fly over the Hudson River in Hoboken, New Jersey. https://www.npr.org/2019/04/07/710847132/big-cities-bright-lights-and-up-to-1-billion-bird-collisions

Addressing this challenge requires a combination of architectural, technological, and policy-oriented solutions. Reducing light pollution is one of the most immediate and cost-effective solutions. The “Lights Out” campaign, launched by the New York City Audubon, encourages building owners to turn off non-essential lights during peak migratory periods. This project has already had some success in reducing bird deaths, but participation remains voluntary. The building design also helps prevent bird crashes. Simple changes, such as patterned glass or window treatments, can assist birds in distinguishing mirroring surfaces from the open sky. These adjustments have been successfully implemented in cities such as Chicago and San Francisco, where similar challenges are being addressed (Sheppard, 2019).

The consequences of unchecked bird fatalities are far-reaching. Birds are crucial to maintaining balanced ecosystems. They are pollinators, seed distributors, and help in pest collection. An urban environment doesn’t make their role any less significant. Studies suggest that birds can help manage pest populations in cities, which could otherwise escalate without natural predators (Lepczyk et al., 2017). The loss of bird populations could create cascading effects, disrupting urban ecosystems and even affecting human residents in subtle ways. Moreover, many bird species are “indicator species,” meaning their health and presence can signal the well-being of broader environmental conditions. A decline in bird populations may point to deeper environmental issues that could eventually impact human health and quality of life.

Figure 4.

Gonzeles, C. (2024). Flocks of Double-crested Cormorants on New York Harbor Island. NYC Bird Alliance

While some building owners and organizations have taken proactive steps, large-scale change requires collective action. Increased public awareness can lead to stronger policies, such as mandating bird-friendly building standards for new constructions or retrofitting older buildings. Efforts to educate the public about turning off lights or modifying home windows can also contribute to reducing bird fatalities. By making small changes, New Yorkers can play a part in preserving entire species of birds and maintaining the city’s environmental diversity.

New York City is currently facing a clash between urban development and wildlife conservation. With better awareness and targeted solutions, however, there is potential to reduce the toll on bird populations. The subsequent blogs in this series will delve deeper into each of these areas, providing readers with a fuller understanding of the problem and offering actionable steps to help address it. By working together, New York can continue to be a world-renowned city while also setting an example for urban sustainability and wildlife conservation.

References

American Bird Conservancy. (2021). Why Birds Collide With Buildings — and What We Can Do About It. Retrieved from https://abcbirds.org

Lepczyk, C. A., La Sorte, F. A., Aronson, M. F., Goddard, M. A., MacGregor-Fors, I., Nilon, C. H., & Warren, P. S. (2017). Global patterns and drivers of urban bird diversity. Proceedings of the Royal Society B: Biological Sciences, 284(1864), 20170850.

Loss, S. R., Will, T., & Marra, P. P. (2014). Estimates of bird collision mortality at wind facilities in the contiguous United States. Biological Conservation, 168, 201–209.

New York City Audubon. (2022). New York City Audubon Bird-Friendly Building Guidelines. Retrieved from https://nycaudubon.org

Sheppard, C. (2019). Bird-Friendly Building Design: Second Edition. American Bird Conservancy.