Every spring and fall, millions of birds migrate through New York City, journeying along the “Atlantic Flyway” from wintering territory in South and Central America to breeding grounds as far north as the Arctic Circle. As this huge variety of birds—from songbirds to raptors to shorebirds—repeat their ancient cycle of migration, they encounter two relatively new threats: glass windows and artificial nighttime lighting. According to NYC Bird Alliance's research, between 90,000 and 230,000 of these migrating birds are killed in the City each year in collisions with building glass. Project Safe Flight is a decades-long campaign to offer these birds safe passage.