Gateway Arch Goes Dark This September to Safeguard Migrating Birds

Every September, the sleek stainless‑steel curve that crowns St. Louis—America’s famed Gateway Arch—does something a little unusual: it switches off its floodlights. It’s a simple gesture, but one that carries big meaning for the feathered travelers soaring overhead.

Since 2002 the National Park Service has dimmed the arch’s exterior lighting during the spring and autumn migrations. The idea is straightforward—bright city lights can confuse birds that migrate at night, leading them to crash into glass or veer off course. By turning the lights off each evening throughout September, officials hope to give the birds a clearer sky.

The Arch sits smack‑dab on the Mississippi Flyway, one of North America’s busiest avian highways. Roughly 40 % of the continent’s migratory waterfowl, plus countless songbirds and raptors, rely on this corridor each year. More than 300 species pass by St. Louis alone, many of them navigating in darkness.

When the arch’s lights go dark, the effect is subtle but significant. Without the glare reflecting off the steel, birds are less likely to become disoriented or to mistake the monument for a safe landing spot. After the peak of the fall migration eases—around early October—the lights will be turned back on, returning the city’s skyline to its usual sparkle.

The Audubon Society, a longtime champion of bird protection, uses the Arch’s dark‑out as a teach‑in moment. Their advice for ordinary folks along the flyway is simple: keep cats indoors during migration, shut off unnecessary outdoor lighting, and make windows more visible with decals or tape. Even something as small as a bird‑friendly glass marker can mean the difference between life and death for a night‑flying warbler.

It’s not just St. Louis that’s grappling with the problem. Last year, New York City’s towering skyline claimed a record‑high number of migratory birds—over 1,250 warblers, flickers, and other species collided with glass panes. That tally topped the previous year’s grim record, underscoring how widespread the issue has become.

Scientists warn that the stakes are getting higher. A 2019 Cornell University study estimated that three billion birds have vanished from North America since 1970. Audubon projects that, without swift action, 389 bird species could disappear from the continent within the next 50 years. The fallout would ripple beyond birdwatchers: about five percent of plant species depend on birds for pollination, and many crops—including coffee and chocolate—rely indirectly on healthy bird populations.

So while the Gateway Arch may look a little less dazzling this month, the quiet it creates overhead is a bright spot for conservation. It’s a reminder that even the grandest monuments can bow to nature when the moment calls for it.