Gateway Arch Goes Dark to Protect Migratory Birds

Every September, the gleaming silhouette of the Gateway Arch over St. Louis takes a little break – its lights are switched off, not for a power‑saving exercise but to protect a massive flock of migrating birds.

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 and hundreds of songbirds travel this route each year, many doing so under cover of darkness. Bright city lights can act like a beacon that leads birds straight into glass or steel, causing fatal collisions.

Since 2002 the National Park Service has dimmed the monument’s exterior lighting twice a year – in May for the spring surge and again in September for the autumn exodus. This year, as the birds begin their south‑bound trek, the Arch’s shimmering outline will fade each evening, resuming its normal glow only after the peak migration period passes in early October.

Conservation groups such as the Audubon Society are using the Arch’s darkening as a teachable moment. They advise homeowners near migration corridors to keep indoor cats indoors, switch off unnecessary outdoor lights, and treat glass with decals or paint so birds can see the barrier. Even something as simple as cleaning bird feeders regularly can help stop the spread of disease among these travelers.

Last year, New York City’s skyline claimed the lives of more than 1,250 warblers, flickers and other species – a grim record that underscores how critical light pollution is. Across the continent, scientists warn that billions of birds have vanished since the 1970s, and without swift action dozens of species could disappear within the next fifty years.

When a monument as beloved as the Gateway Arch chooses to go dark, it’s a quiet reminder that human icons can, and sometimes must, bow to nature. It’s a small step, but for the millions of feathered wayfarers crossing the Midwest, it could be the difference between life and a tragic collision.