ST. LOUIS—The National Park Service has announced it will not illuminate the Gateway Arch at night September 18-30, due to bird migration season.

“This time of the year, it is very common to see our feathered friends flying south for the winter,” said Pam Sanfilippo, Chief of Museum Services and Interpretation, Gateway Arch National Park. “Every bird migration season, we turn off the upward lighting on the Gateway Arch’s exterior to avoid the possible disorienting effect on birds that migrate at night.”

The exterior lights will be turned back on beginning Thursday, October 1, and the monument will be lit nightly thereafter.