Last October, birds winged their way through Philadelphia, following the north-south path of their annual migration toward warmer weather.

But the journey ended in disaster for many birds. As they flew through the city, they became confused by the artificial lights of Philadelphia’s downtown skyscrapers. On the morning of Oct. 2, volunteers found over 1,000 dead and injured birds that had collided with buildings and glass.

This year will be different: A group called Bird Safe Philly is organizing an effort to dim the city’s downtown during spring and fall migration periods.

Conservationists, city officials and downtown property owners recently announced their participation in the national Lights Out initiative, which calls on properties to turn off as many lights as possible at nighttime to protect migrating birds.

Some of the city’s tallest buildings — including Comcast Technology Center, Comcast Center, One and Two Liberty Place and the BNY Mellon Center — plan to participate. The national Lights Out program is sponsored by the Audubon Society and has spread to 33 other cities.

The route birds take on their annual migration through the eastern United States is known as the Atlantic Flyway. Birds such as the black-throated blue warbler, common yellowthroat and ovenbird were among the dead during the mass bird strike event last year. This isn’t the first time birds died en masse while traveling through the city: A similar collision happened in 1948, and other mass deaths occur all over the United States.

Both building glass and lighting at all heights can disorient birds. The birds are especially drawn toward lighting during inclement weather. And bird strikes don’t just happen with tall buildings. According to the U.S. Fish and Wildlife Service, 56% of bird strike mortality happens with low-rise buildings and 44% at urban and rural residences.

You can participate, too, by reducing exterior lighting at night.