At Jefferson National Expansion Memorial, the Gateway Arch floodlights will remain turned off at night during the last two weeks of September. If migrating birds could talk, they’d say “thanks a million!”
Birds that migrate at night -- primarily to avoid predators and strong daytime winds – tend to heavily rely on the stars for navigation. They can become very confused when flying in densely built-up areas with thousands of artificial lights, including many that are high off the ground. The disorienting effect is especially great during rainy or foggy weather, and in the wee hours of the morning when the birds descend from normal migration altitudes.
Cities along flyways, commonly rivers and lakeshores, create severe problems for the night-migrating birds. Within the cities, skyscrapers and tall office buildings pose the greatest hazard because of their greater height and abundant lighting. Some birds that are distracted by lights veer away from the flyways and temporarily lose their way. Some flutter near bright lights until they are exhausted and fall to the ground. Many die in collisions with buildings and brightly lit windows.
Turning off unneeded interior and exterior lights in cities during the peak migration periods can dramatically reduce bird mortality in urban centers. Many cities accordingly participate in “lights out” programs that are sponsored or approved by the Audubon Society and other bird-friendly NGOs. As a bonus, turning off lights, closing curtains, and drawing blinds saves energy.
In cooperation with the Audubon Society and the City of St. Louis, the National Park Service is doing its part by turning off the floodlights of the Gateway Arch each night during the last two weeks of September, a time when the fall migration peaks. The 630-foot high Gateway Arch, the star attraction of the Jefferson National Expansion Memorial (and the city’s signature landmark) will be floodlit again beginning in October.
Another two-week “lights out” is scheduled at for the Arch next spring when the birds head north to their breeding grounds.
Postscript: The Gateway Arch has not always been floodlit. Although completed in 1965, this architectural icon wasn’t equipped with floodlights until 2001. The Arch was at first lit only three hours each night (9:00 p.m. until midnight), but more hours were added after St. Louis residents complained that three hours wasn’t enough.