Philly will dim its lights to make it skies more bird-safe
The lights of Philadelphia might not shine as bright in the coming weeks as a coalition in the City of Brotherly Love tries to prevent millions of migrating birds that pass through twice a year from slamming into skyscrapers and crashing to the sidewalk.
Bird Safe Philly on Thursday announced the Lights Out Philly initiative, a voluntary program in which as many external and internal lights in buildings are turned off or dimmed at night during the spring and fall.
The problem of artificial lights attracting birds to their deaths in the city is not new.
“We have specimens in the academy’s ornithology collection from a kill that happened when lights were first installed on Philadelphia’s City Hall tower in 1896,” said Jason Weckstein, associate curator of ornithology at Drexel University’s Academy of Natural Sciences.
The coalition, which includes Audubon Mid-Atlantic, the Academy of Natural Sciences of Drexel University, the Delaware Valley Ornithological Club and two local Audubon chapters, formed after the city’s largest mass-collision event in 70 years was reported in October.
Hundreds of dead birds were found around the city.
“Conditions were perfect for a heavy migratory flight and imperfect given that there was a low ceiling of clouds and rain,” Weckstein said. “That in combination with Philly’s bright city lights was a disaster for many fall migrant birds winging their way south.”
Birds navigate during migration using celestial cues, and when they cannot see stars on a cloudy night they get confused by bright city lights, according to experts.
Windows pose a problem, according to Weckstein, because many birds might see a reflection of trees or the sky.
Scientists estimate that 365 million to 1 billion birds are killed by collisions with
buildings or other outdoor structures in the U.S. every year, and those crashes are taking a toll on some species.
Common yellowthroats, white-throated sparrows, gray catbirds and ovenbirds are the most common victims in Philadelphia, experts said, and those species also are being threatened by climate change and other predators.
“The ovenbird and the black-throated blue warbler are among the hundreds of bird species that are now at an increased risk of extinction in North America because of climate change,” said Keith Russell with Audubon Mid-Atlantic. “But many of these species also face the additional threat of colliding with buildings.”