Philadelphia lies in a major path for millions of birds navigating the Atlantic Flyway, an especially busy avian skyway each spring.

Starting April 1, some of Philadelphia’s most iconic skyscrapers — Comcast Technology Center, Cira Centre, and Liberty Place — will turn off, or turn down, their lights to help prevent birds from flying into buildings under Lights Out Philly, a program started in spring 2021. Scores of buildings will participate.

It’s estimated that 1,000 birds die each year in just a four-block area of Center City with a rough radius spanning 17th to 19th and Market to Arch. Thousands more are killed after striking low-slung buildings in other parts of the city. Overall, it’s estimated that as many as one billion birds fly into buildings in the United States annually.

The problem is more acute in spring and fall when migrating birds are flying to or from Canada, Central and South America, the West Indies and elsewhere. Most birds migrate at night and can become lured by artificial lights into buildings and windows.

Lights Out Philly is part of a National Audubon Society program. About 45 cities participate, as well as seven states and regions. Under Lights Out Philly, building owners or management voluntarily darken their lights from midnight to 6 a.m. twice a year: April 1 to May 31, and Aug. 15 to Nov. 15. Proponents say that turning off lights also reduces use of fossil fuels and saves businesses money.

“All of us involved are thrilled that the program has gone so well,” said Keith Russell, program manager for urban conservation at Audubon Mid-Atlantic. “We had an excellent beginning. It’s going to take some work to expand it, but there were plenty of other buildings that could certainly be involved. We’ve got hundreds of thousands of buildings in the city.”

‘Bird Safe’

Locally, Lights Out Philly is run by Bird Safe Philly, a partnership led by the Academy of Natural Sciences of Drexel University and including Audubon Mid-Atlantic, Delaware Valley Ornithological Club, National Audubon Society, Valley Forge Audubon Society, and Wyncote Audubon Society. The goal is to create safe spaces for birds and to develop awareness of bird accidents.

Bird Safe Philly was formed after The Inquirer reported in October 2020 that an estimated 1,000 to 1,500 birds flew into buildings in the four-block radius of Center City over one night and into early morning. The article drew international attention in what a Philadelphia-based Audubon volunteer, Stephen Maciejewski, called a “perfect storm” of avian calamity. He found the birds and estimated that thousands more could have perished elsewhere in the city that day.

Maciejewski said Monday that with not quite two complete years of data, preliminary numbers show Lights Out Philly appears to be having an impact.

“I know it’s helping, but we only started this in April of 2021,” Maciejewski said. “That’s not a lot of data.”

He’s seen a dramatic success at a two-story atrium near 17th and Market. In the past, Maciejewski said, the atrium was “lit up like a beacon.” But, bird deaths have dropped 70% since lights have been turned off in spring and fall.

Avian navigation

Birds use a variety of ways to navigate at night, including cues from the earth’s magnetic field and positions of stars. Weather, such as low cloud cover, can push birds lower, meaning they no longer have stars as a guide. Artificial lights can disorient them.

Some flying from remote Northern habitats might have little experience with glass. As birds reach Philly in the dark, they are attracted to the lights inside the buildings. Some of the skyscrapers have indoor atriums, which could have led birds to think they could land there. On any given morning, street trees reflect in the glass, making it appear that they are inside buildings.

Participating buildings are asked to turn off all unnecessary lights, especially those on upper levels, lobbies, atriums, and exteriors. That includes lights at the top of buildings known as crowns, facades, atriums, and lobbies. It includes flood and decorative lights. Management also asks tenants to turn off interior lights, especially those closest to windows.

Kristine Kiphorn, executive director of BOMA, a group of building owners and managers, said she’s gotten reports that the bird deaths have decreased, dramatically in some cases, since the program started. Anywhere from 40 to 50 buildings usually participate.

“We’ve had such a robust response to this and such great participation from our members that it just makes sense,” Kiphorn said. “And it’s the right thing to do. It makes sense to help preserve the bird population. It’s also environmentally friendly.”