Urban Lights Severly Infringe On Bird Migrations
This is exactly what the researchers found at the Tribute in Light. They measured more than 20 times the density of birds near the memorial than in surrounding areas. The birds spent long periods circling inside of the cone of illumination and they vocalized frequently. This meant that they were using precious energy, but not making any progress on their migration routes. Some died of exhaustion, while others collided with nearby buildings.