The natural cycle of day and night helps keep all living things in balance. A rhythm of sunny days and dark nights is known as a circadian rhythm. Like humans, many species of plants, animals, and insects have adapted to be active at specific times.
Species that are active at night are called nocturnal. Natural darkness is vital for nocturnal wildlife to find food, avoid predators, move between habitats, and even locate mates. Reducing unnecessary artificial lighting helps maintain these natural cycles and supports healthier ecosystems.
Organizations like DarkSky International promote simple practices that protect the night environment, including shielding lights so they point downward, using warmer-colored bulbs, and turning off lights when they are not needed.
Protecting the night sky also reveals something remarkable happening above us.
Estimated nocturnal bird migration across North America based on weather radar data. Source: BirdCast, Cornell Lab of Ornithology.
To bird enthusiasts, the night sky is far from empty. Most North American songbirds migrate after sunset, traveling hundreds of miles before dawn. Radar tools developed by the Cornell Lab of Ornithology allow us to see this movement through the BirdCast migration maps.
During peak migration seasons, millions of birds fly over Missouri while we sleep. One recent spring night saw more than 33 million birds estimated to pass over the southern portions of the US.
This technology changes how we think about the quiet hours before dawn. The warblers, thrushes, and sparrows we enjoy hearing in the morning may have arrived only hours earlier after traveling through the darkness above.
Migration occurs across broad seasonal windows, but the most intense movement usually happens during predictable time frames:
Spring migration: approximately March through mid-May
Fall migration: approximately August through mid-October
During these weeks, restored landscapes like the Cardinal Valley Habitat Restoration Area provide valuable stopover habitat where migrating birds can rest and refuel.
Protecting the night sky helps migrating birds and many other nocturnal species that depend on natural darkness.
Simple actions include:
Turning off unnecessary outdoor lighting
Reducing the intensity of necessary lighting
Add timers or motion sensors
Using warmer-colored bulbs, such as yellow or amber
Installing shields that direct light downward toward the intended area
When we protect the night, we are not only saving energy, we are also helping sustain the many species that depend on the natural rhythms of darkness.
Sources:
BirdCast migration maps, Cornell Lab of Ornithology — BirdCast Live Migration Map
Dark sky conservation information, DarkSky International —DarkSky.org