magnet for thousands of confused migratory birds that were heading south for the winter.
In a sight that was documented by many YouTube videos, the birds flocked to the beams, flying around in circles, unable to head away from the light.
"This was an epic night for migration," John Rowden of the conservation group New York City Audubon told AOL News. "Conservatively, we had tens of thousands of birds."
Eventually, authorities had to shut off the beams five times last Saturday night to allow the birds to escape, The Daily Telegraph reported.
Migratory birds use lights in the sky, such as the stars and the moon, to navigate on their long journey south each winter. Saturday was a new moon, and large numbers of birds had gathered in the New York area after bad weather prevented them from flying further south.
With the stars obscured by ambient city light and no moon in the sky, the birds latched on to the Tribute in Light. Unfortunately, with the two beams as the only point for navigation, the birds were unable to fly away from the memorial.
"They were sort of doing figure eights," Rowden said. "They just couldn't navigate out."
It was a striking sight, but these birds were in real danger, Rowden said, explaining that constantly flying without going anywhere could exhaust the birds, threatening their ability to continue south and find food.
According to the Canadian conservation group Fatal Light Awareness Program, more birds die from collisions each year than died as a result of the Exxon Valdez oil spill.
Since 2003, buildings in downtown Chicago have dimmed their lights on spring and fall nights to prevent birds from flying into them. In 2007, Toronto issued guidelines for architects and developers to make their buildings more bird-friendly.