By Dan Zarlenga, Missouri Department of Conservation
Photo Caption: Help birds find their way during peak migration times in May and September by practicing responsible outdoor lighting. Photo courtesy of the Missouri Department of Conservation.
Did you know that the St. Louis area lies right in one of the greatest migration routes for birds on the entire North American Continent? It’s the Mississippi Flyway. Birds follow the great river’s corridor in the spring and fall to travel to and from their nesting grounds and their summer homes. The peak of spring migration occurs in May, and the autumn peak is this month, in September.
Now another question: when do most birds do their migrating? It turns out, a whopping 80% of these birds travel during the dark of night! The only problem is those nights are not as dark as they used to be.
Birds utilize the moon and stars for navigational cues, just like the mariners of old. Birds discovered the trick long before humans did; it’s an amazing adaption gifted to them through evolution. Flying is also easier during the night because the atmosphere is more stable. The calmer air is especially helpful for smaller birds like warblers and other songbirds, which don’t fly very rapidly. Cooler nocturnal temperatures might also help birds avoid overheating on long flights. Add the fact that there tends to be fewer predators out hunting after sundown, and migrating at night becomes a no-brainer.
Unfortunately, as the birds pass over big cities, they can become disoriented by bright artificial lights and sky glow that have washed out the stars from urban areas. This makes navigating for these avian flyers a lot more difficult by obscuring their points of reference. Plus, it’s estimated that 600 million birds in the U.S. die each year from collisions with buildings during these night flights.
A study by Cornell Lab of Ornithology ranked metropolitan areas in Missouri, Kansas, and Illinois where birds are at the greatest risk of becoming attracted to and disoriented by lights and crash into buildings. St. Louis ranked 5th most dangerous city to migrating birds in spring, and 6th during the fall.
But there are ways we can help by using responsible outdoor lighting when bird migration peaks in May and September, and even better yet, throughout the entire year! It’s simple; turn off outdoor lights if they are not needed.
Just be guided by the “Five Principles for Responsible Outdoor Lighting”:
- Use light only if it is really needed.
- Direct light so falls only where it is truly useful.
- Use lights that are no brighter than necessary.
- Turn lights on only when and for as long as actually required.
- Use warmer colored lights if possible.
In addition, these steps will save on energy bills! Get more information and helpful suggestions by going to LightsOutHeartland.org. The Missouri Department of Conservation participates in the Lights Out Heartland collaboration, spearheaded by the Missouri Chapter the International Dark-Sky Association. The goal is to raise awareness of and reduce light pollution during bird migration periods.
So, consider our avian friends this month at their crucial migration time. You can make a difference by reducing unnecessary nighttime illumination around your home and helping to spread the word. Turn off lights to show the way for migrating birds!