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Manhattan's East River skyline from Roosevelt island (Stock photo) Manhattan's East River skyline from Roosevelt island (Stock photo)
Earlier this week, the annual Tribute in Light went up to honor the memory of those lost in the 9/11 attacks. While a moving sight for New Yorkers to behold, it causes confusion among migratory birds. Considering birds are drawn to light as moths are to flames, this is not surprising. The excessive lights cause birds to collide with buildings and/or the lights can cause birds to circle buildings repeatedly and confuse and exhaust them. Exhausted birds then go to roost in places they shouldn’t and this leads to their demise.

This is especially pronounced on the sidewalks surrounding New York City’s all-glass buildings that have risen in both popularity and stature. According to research by the Audubon Society, up to 230,000 birds are killed each year when they collide with building glass. Artificial lights lure them into the city; between reflections of trees in the glass and the sight of shrubbery and/or green walls inside, the birds see what looks like a promising place to roost and fly headlong into the glass.
It can be upsetting to see a dead bird on the sidewalk at any time, but this takes place against a backdrop when bird populations are declining all over the world in the wake of climate change and deforestation. This article explores why this happens, what New York can do about it, and cues we can take from other cities that have saved birds’ lives.
90,000-250,000 birds are killed annually in New York City.

Why does this happen?

Bright lights cause birds to override their intuitive navigational guides, like the earth’s magnetic pull and the alignment of planets. Additionally, research has proven that birds cannot see glass. So as the sun sets and lights remain on inside buildings throughout the night, the birds will fly straight into the glass.

According to Dr. Susan Elbin, the New York City Audubon's Director of Conservation and an ornithologist who has worked in the field of behavioral ecology and conservation for more than 25 years, not all light is created equal. The light that causes the most confusion to birds is light directed straight up into the sky. Steady beams are worse for birds versus flashing or strobe. In terms of colors, green and blue light are the least distracting color for birds. Yellow and red lights are not great, and white is the worst.
Tribute in Light, September 11, 2018 Tribute in Light, September 11, 2018, 8:40 p.m. (Courtesy of

What can we learn from other cities?

Toronto and Chicago both seem to be shining brightly by dimming their lights. Toronto’s Fatal Light Awareness Program (FLAP), with its very sad real-time estimator of bird deaths, was founded 25 years ago. FLAP estimates estimated 1.5 - 2 billion migratory birds are killed across North America as a direct result of human activity. Bird-building collisions are the number one killer. FLAP offers a number of solutions, between advising homeowners on bird-safe window markers and consulting with commercial and institutional building owners on ways to make their structures safer. It is also worth pointing out the financial benefits Toronto has experienced: When Toronto’s Metro Hall building followed the bird-friendly rating system, they reported an annual savings of $200,000 in energy costs.

According to Chicago’s Lights Out program, “Since 1995, Chicago’s tall buildings in the Loop have served as an example to the nation as they save 10,000 birds’ lives annually by participating in the Lights Out program. In addition to saving migratory birds, building owners have realized direct benefits, including decreased energy and maintenance costs.” In downtown Chicago, it is estimated approximately 100 buildings dim their lights between 11 pm and dawn for six months of the year. A 2021 study found that shutting off half the lights in large buildings could reduce collisions by as many as eleven times.
New York introduced its own Lights Out program in 2005, but it didn't catch on well. Dr. Elbin attributes this to four things: lack of funding, absentee owners, the system of check-ups and perceived security.

Firstly, Elbin admits the NYC Audubon does not have the funding to put the force behind this cause that is desired and necessary. Secondly, she says it is very difficult to find the actual building owners as many are absentee owners. Thirdly, currently, the only way to follow up with the buildings is with the honor system.

Lastly, Elbin says many building owners incorrectly assume dimming the lights will lessen the security of the building and therefore they do not want to be involved. To that, Elbin suggests motion activated lights not only do the job but provide more security that lights left on constantly because they attract attention when they go on.
Lights satellite NYC Satellite image of lights seen throughout NYC and New Jersey

What actions has New York taken?

While the Lights Out program was not as successful as some hoped, that is not to say the city is not working on saving birds. At the end of 2019, the New York City Council enacted legislation requiring that all new construction and major building alterations must incorporate special materials, such as patterned glass or glass with ultraviolet coating visible to birds but not humans, so as to avoid avian strikes. This has worked before. A spokesperson for One World Trade Center told the Associated Press that the first 200 feet of the tower are encased in non-reflective glass fins specifically chosen to reduce bird strikes. Further uptown, the Javits Center was once named one of New York's deadliest buildings for birds. However, after refurbishing the building with patterned glass that were interpreted as obstacles, bird deaths dropped by 90 percent. Indeed, with its rooftop terrace and farm, it might have gone from the deadliest to the friendliest building for birds.

Francisco Moya, a City Councilmember representing East Elmhurst, Jackson Heights, and Corona, is prepared to take it further, having introduced legislation that would require commercial buildings to turn off their lights through the night unless someone is inside and working; government buildings already do so, and there would be exemptions for landmarked buildings and small stores. Not only would the darkened buildings no longer serve as a lure to birds, but it would have a positive effect on the city’s carbon footprint as a whole.

Additional Info About the Building

Contributing Writer Michelle Sinclair Colman Michelle writes children's books and also writes articles about architecture, design and real estate. Those two passions came together in Michelle's first children's book, "Urban Babies Wear Black." Michelle has a Master's degree in Sociology from the University of Minnesota and a Master's degree in the Cities Program from the London School of Economics.