^{NYC Bird Alliance volunteers monitoring birds circling in the 2023 9/11 Tribute in Light Memorial. Photo: NYC Bird Alliance}

By Katherine Chen

Every night, the bright lights of New York City draw birds in. There’s one night in particular when the lights shine brighter than ever, and when NYC Bird Alliance has a critical role to play: September 11. This year’s 9/11 Tribute in Light Memorial, while a poignant reflection on the tragic events of that terrible day, was particularly hazardous to birds.

For over 20 years, NYC Bird Alliance scientists have been granted access to monitor the twin beams of the Tribute, consisting of 88 high-powered spotlights. The Tribute shines throughout the night of September 11 and can be seen throughout the City as a somber reminder of the tragedy.

Night-migrating birds are naturally drawn to sources of light, and the Tribute beams—which can reach up to four miles high—pose a significant risk. NYC Bird Alliance scientists, stationed at the base of the Tribute atop the Battery Parking Garage in Lower Manhattan near Ground Zero, see that birds become “trapped” within the lights. The birds can circle endlessly, leading to exhaustion and disorientation, making them more susceptible to collisions with windows. 

Our partners at the National September 11 Memorial & Museum and Michael Ahern Production Services respect and honor NYC Bird Alliance’s requests to save the wildlife caught in the beams. If our volunteers count more than one thousand birds circling in the beams at one time, or if birds are observed circling and calling low in the beams, we ask for the lights to be shut off for a brief period. The moment of darkness allows birds that have been disoriented from the lights to disperse from that area and continue on their journey.

This year, 40 community scientists made up of NYC Bird Alliance staff, board members, and volunteers, coupled with several representatives of the Cornell Lab of Ornithology, helped our conservation team monitor the beams throughout the night.

Weather and migration patterns strongly influence the number of birds we see at the Tribute in Light, and this year we arrived at the garage roof apprehensive. In the days leading up to the Tribute, we kept a close eye on BirdCast, which predicted “medium” migration intensity on the night of September 11. In addition, heavy rain through the afternoon and early evening stopped right before the lights went on, leaving a low cloud ceiling which can amplify the appearance of the beams, dispersing light and causing birds to fly lower. Although more pleasant for the humans on the garage roof who remembered last year’s heavy rain on September 11, 2022, the combination of these factors made us fear large numbers of birds in the beams that night. 

The fear mounted early in the evening, as we observed several birds circling the beams soon after the lights were turned on. The number quickly increased, as the birds simultaneously moved lower in the lights, and made frequent flight calls. We hesitated, not wanting to turn the lights off when New Yorkers were still awake and admiring the beams across the City. However, just before 10pm, the earliest we’ve ever had to request in our two decades of monitoring, the volume of birds was too great and we asked for the lights to be shut off for the first time that night.

 
Once the lights were off, we saw the birds quickly disperse. For the first time, in partnership with researchers from the Cornell Lab of Ornithology, we tested a thermal camera that allowed us to record bird movements in the dark night sky and to visually document the behavior of trapped birds after the Tribute lights go out. (We have begun more in-depth analysis of the video and expect the results will provide insights into dispersal of birds related to artificial light.) 

After twenty minutes, per our agreement with the memorial producers, the lights turned back on. Our scientists saw that the birds immediately returned, congregating in the beams. Less than half an hour later, at 10:39pm, we requested another lights-off period. A twenty-minute dark pause, and once again, upon relighting, the birds quickly returned. The lights were turned off for a third time at 11:41pm, and then again at 2:52am. Shutting off the lights four times made for one of the busiest nights we have had on the roof since we started monitoring in 2001. 

Finally, the number of circling birds began to decrease around 5am; dawn broke at 6am, and the lights were powered off for good. As we broke down camp, a resident pigeon greeted us “good morning,” passing through—but not staying in—the lights. 

In addition to observing birds stuck in the beams, our scientists were concerned about collisions. A relatively new building has gone up at 50 West Street, with windows dangerously near the Tribute’s North beam. We observed several collisions with those windows throughout the night. One of them, a Black-and-white Warbler, was rescued by NYC Bird Alliance’s Board President Karen Benfield, who brought it to our partners at the Wild Bird Fund, where it was treated for a likely concussion and then, fortunately, released two days later. 

In addition to Black-and-white Warblers, NYC Bird Alliance’s volunteers identified Common Nighthawks, Connecticut Warblers, Northern Parulas, and American Kestrels, as well as bats, katydids, Spotted Lanternflies, and other insects. 

The 9/11 Tribute in Light Memorial is a stark reminder of the effects of artificial light at night on birds. What happens at Ground Zero on September 11 happens all over the city during spring and fall migration as a result of the City’s lit buildings. It is estimated that nearly a quarter million birds die every year in New York City as a result of collisions with buildings. 

NYC Bird Alliance is actively and energetically involved in the fight to curb artificial light at night in New York City to protect migratory birds. Working with our partners at the Lights Out Coalition, we are championing a new Lights Out bill, Intro 1039 in City Council, that will require privately owned commercial and industrial buildings to turn lights off at night. 

Learn more about the bill and how you can help get it passed on our Lights Out Legislation page.