ST. LOUIS, Mo. – A massive bird migration is about to make the annual trip north through the United States. Many of the birds will make their way through the Midwest near the Mississippi River at night. City lights have a big impact on if the birds will survive their epic journey. Geese, warblers, sparrows, and many more birds migrate at night.
The Illinois Department of Natural Resources is among the organizations asking people to turn off their lights on certain nights. Those nights are when large migrations are coming through the area. For instance, the lights illuminating the Gateway Arch typically go dark in May and September for the annual bird migrations.
You can see which nights are the best to turn off the lights by tracking the birds. A service called “BirdCast” shows you where the flocks are heading each night. The maps show the predicted path of nocturnal migration three hours after sunset. You can also sign up for local alerts here. Colorado State University and the Cornell Lab of Ornithology currently produce these forecasts
A recent study from Cornell Lab says that St. Louis is the 5th most dangerous for birds during migration. St. Louis Audubon Society reports that the region is along a major migration path that which 60% of North American songbirds and 40% of North American waterfowl use to travel north or south.
Most dangerous cities for migrating birds in the spring:
- Los Angeles
- St. Louis
- Kansas City
- New York
- San Antonio
Why is light pollution so dangerous for birds?
“Light pollution poses a challenge for the many birds that migrate at night. Birds can be confused by bright lights and skyglow as they migrate. They become exhausted leading to collisions with buildings or landing and in dangerous areas with buildings containing substantial amounts of transparent or reflective glass. Birds do not see glass as a barrier, so they may try to fly through transparent glass or fly to trees and vegetation reflected in mirror glass. This often leads to collisions, injury and, unfortunately, sometimes death.”St. Louis Audubon Society
The St. Louis Audubon Society is working with local businesses and homeowners to limit light pollution. They have two programs to address the issue. One works with businesses downtown to limit light in the urban environment. The other tracks the number of birds dying during migration through the area. Surveys conducted during the fall 2020 migration found over 600 dead or injured birds over three migration periods. The group says that it is likely an underrepresentation of the total number.