ST. LOUIS – The lights of the St. Louis Gateway Arch will be turned off throughout the month of May due to the spring bird migration season. According to the National Audubon Society, most birds fly at night.

Birds utilize the stars and moon for navigation, and the stable atmosphere at night helps them stay on course, which is particularly beneficial for smaller, slower-flying birds.

The Gateway Arch is situated along a major migration route. For over a decade, the Arch has turned off its lights to assist these birds. However, since 2002, migration patterns have shifted. Instead of turning off the lights nightly for two weeks, the park will now do so for the entire month of May.

The National Park Service began turning off the Gateway Arch’s exterior lights to protect migrating birds in 2002. The Arch’s exterior lights will be turned back on starting the evening of Thursday, June 1, 2023, and the monument will be lit nightly thereafter.