On September 11, two powerful beams of light once again projected more than four miles into the night sky from Lower Manhattan. Known as the Tribute in Light, this annual light installation beautifully honors the thousands of lives lost on September 11, 2001. The Tribute is a stirring and fitting reminder of the tragic events of 9/11, but it can also be a hazard for hundreds of thousands of migratory birds that travel through the city under the cover of darkness during their fall migrations. Birds are attracted to light, and can end up trapped in the Tribute’s powerful beams—circling, calling, and wasting precious body fat that fuels their migratory flight.
Since 2002, New York City Audubon has monitored the Tribute in Light to look for birds that have become caught in the beams. An agreement was put in place in 2005 with the producers of the Tribute (now the National September 11 Memorial & Museum and Michael Ahern Production Services) to turn off the lights for a brief period if need be to allow any trapped birds to disperse. The agreement allows this important Tribute to continue honoring the lives lost on 9/11 while minimizing the Tribute’s impact of night-migrating birds. We deeply thank National September 11 Memorial & Museum and Michael Ahern Production Services for their continued consideration of the birds. Weather and migration patterns strongly influence the number of birds we see at the Tribute in Light. This year we arrived at the Tribute concerned: the weather was clearing up after a recent rash of storms, meaning migrant birds might take flight in large numbers that night. Additionally, there were low-level clouds and increasing fog, factors that can cause birds to be drawn to strong beams of artificial light at night in large numbers. NYC Audubon staff and volunteers were joined again this year by scientists from the BirdCast team at the Cornell Lab of Ornithology. Team members installed an automatic acoustic recording unit to record avian flight calls and also kept us apprised of bad weather and birds heading for NYC as seen on their radar maps. As the sun set and the beams became visible, all eyes were on the sky. The number of birds began increasing around 10 p.m., circling high in the beams where the lights met in the sky. Eventually, birds became visible lower in the beams. Yellow Warblers, Ovenbirds, American Redstarts, and others could be clearly seen and heard calling above our heads. Another concern this year was 50 West Street, a tall building constructed in 2016 that rises directly next to the lights of the north beam. Birds could be seen fluttering dangerously close to the glass facade.
At 10:50 p.m. NYC Audubon’s Dr. Susan Elbin requested the lights be turned off for 20 minutes for the safety of the birds. Once the lights were turned back on, our team was pleased to observe that not only had the birds dispersed, but the number of migrants in the area (as seen on Cornell Lab’s radar map) had declined—possibly grounded by weather to the north of us. Over the next few hours only occasional small groups of birds could be seen flying through the beams. The lights were again shut off for a brief period at 2:15 a.m., when we observed birds flying low over the lights and perilously close to the reflective glass of 50 West Street. The night went on without further incident, and as the sun rose at 6:00 a.m. our stalwart team observed the few remaining birds hunting insects as the beams faded into the sunrise. In addition to bird monitoring, we once again recorded bat echolocation calls at the Tribute. This year friends from the NYC Bat Group and Bat Conservation International joined and brought the latest in bat recording technology (donated by Wildlife Acoustics) for us to try out. Using the technology we were able to detect Eastern Red Bats and Hoary Bats hunting in the beams. We were also joined for the second year in a row by Graham Montgomery, a scientist from the University of Connecticut who worked with the lighting crew to collect arthropod specimens that settled on the spotlights. We look forward to learning the results from this years’ observations as soon as the team members recover from their ‘all-nighter’ of observation and complete the analysis.
-Kaitlyn Parkins, Conservation Biologist
Be sure to check out NYC Audubon’s Facebook page or our Twitter page for more photos and video from the event. To learn more about the work NYC Audubon does to protect migrating birds, visit our Project Safe Flight page. New York City Audubon’s Project Safe Flight program is made possible by the leadership support of the Leon Levy Foundation.
