Most migratory birds in North America use the night sky to navigate their way between north and south every year. However, as they pass over big cities, they can get disoriented by bright artificial lights and skyglow, often causing them to collide with buildings or other outdoor structures. This leads to hundreds of millions of migratory birds dying in the US every year, some of which belong to species already under threat because of climate change.

In an effort to help make it safer for birds to travel through Philadelphia, a new partnership, called Bird-Safe Philly, has recently launched a project aimed at dimming the city’s lights during the migration period of birds. Dubbed Lights Out Philly, the initiative is a voluntary program in which as many external and internal lights as possible are turned off or dimmed at night during the spring and fall.

As reported by the Associated Press, between 365 million and one billion birds die because of collisions with buildings and windows in the US alone. Those crashes are affecting dozens of vulnerable species. Among the most common victims are the white-throated sparrows, gray catbirds, and ovenbirds, which are also threatened by climate change and other urban dangers.

Decreasing the light buildings emit not only can minimize unnecessary bird fatalities but also help reduce energy consumption, potentially slowing down climate change. The Lights Out Philly initiative will run from April 1 through May 31 and from August 15 to November 15.

The Building Owners and Managers Association of Philadelphia (BOMA), to which many of the city’s commercial property owners and managers belong, said the response so far has been “extremely robust.”

“We have some early adopters and the list is approaching 20 buildings, many of which are iconic and very recognizable members of the Philadelphia skyline, such as One and Two Liberty Place, Comcast Technology Center, and Comcast Center,” said BOMA executive director Kristine Kiphorn.

“We get to do our part in the community to help preserve the bird population, and we get to conserve energy at the same time, saving money for our tenants and our assets,” added Kiphorn.