This year's 9/11 memorial tribute ended up mesmerizing and trapping some 10,000 birds as they headed south for the winter. The Tribute of Light—beams of light projected where the Twin Towers once stood—was the brightest light in the area on that overcast night and birds relying on starlight to navigate ended up bedazzled and pulled from their path, the Telegraph reports.
The birds circled around in the beams, wasting vital energy needed for the trip south. Organizers switched the beams off for 20 minutes five times throughout the night to allow the birds to escape. The problem has only happened once before during the 2004 tribute. "It’s a confluence of circumstances that come together to cause this,” an Audubon Society official tells Wired. “Some of it has to do with meteorological conditions, and some with the phase of the moon.”