PHILADELPHIA, Pa. — Soaring skylines gleaming against the inky darkness: it’s a defining feature of most cities at night.
Yet, those towering triumphs come with a dark side.
“Basically, around a billion birds here in the U.S. are killed by running into buildings,” said ornithologist Jason Weckstein with The Academy of Natural Sciences of Drexel University in Philadelphia.
More than 220,000 birds are carefully cataloged and studied there - many of them killed after crashing into buildings.
“We get those things with broken bills. They’re flying so hard and so direct, when they hit that building, it’s a hard impact,” he said. “We do know that birds are attracted to light. So, a lot of these birds are nocturnal migrants, and nocturnal migrants use a variety of cues to navigate while they're migrating in the spring and the fall.”
One night in October 2020, it all went terribly wrong in Philadelphia and several other cities in the Northeast.
“When this was reported, people were like, ‘Oh, my gosh, we have to do something,’” Weckstein said.
Thousands of birds died in a massive collision that night just in Philadelphia alone.
Keith Russell with Audubon Mid-Atlantic and program manager for urban conservation collected more than 1,000 dead birds within a few blocks.
“One building alone, you know, may have had as many as five or 600 birds,” Russell said.
The problem is two-fold: bright lights on buildings and the use of reflective glass in their construction.
So, Russell and others decided something needed to change, which is how "Lights Out Philly" came to be.
“Glass is a difficult thing to do anything about,” Russell said. “So, one thing we can do to stop these collisions is to address the light issue. So, we do that by enacting ‘Lights Out Programs.’”
Lights Out Programs are now in place across the country in more than 40 cities. It’s a voluntary program. From midnight to 6 a.m., many downtown buildings turn off their lights during the spring bird migration in April and May and again for the fall migration.
“When they're migrating, they need to have ways of finding their way,” Russell said. “And one of the ways they do this is to be able to detect the Earth's magnetic field and that involves them being sensitive to certain wavelengths of light.”
Turning off the building lights help birds migrate safely. It’s not just skyscrapers, though: homeowners can make a difference, too, during migration season.
“People that have homes can do the same thing,” Russell said. “They can turn their lights out at night, pull down shades, pull down blinds, pull down other windows, you know, treatments that will block a bird’s ability to see into your house after the sun goes down.”
It's a simple step that brings with it not one, but two potential benefits.
“Turn your lights down,” Weckstein said. “You don't spend as much on electricity and you may be saving some birds that way.”