Protect our Dark Skies

Light pollution is a global problem

Have you had this experience of sleeping in a new place: you turn off the light to go to bed, and realize that there is a bright light illuminating your room, leading to a restless night of sleep? If this has happened to you, you are not alone! Much of the world lives with light pollution: 80% of the human population lives under a lit sky, while 30% of people cannot see the milky way due to light pollution (National Geographic, NPR). Light pollution has been shown to have negative health effects not just for humans, but also for our wild neighbors. In honor of Dark Sky week, we wanted to share some of the ways light pollution affects birds, their insect food, and what you can do to help!

Aerial satellite image of night-time light pollution in the Great Lakes Region. Photo credit: NASA/ NOAA

Creatures of the night like it dark

Many animals are nocturnal – 30% vertebrates and more than 60% invertebrates. Most organisms have biological clocks based on night-day cycles. For birds, light pollution has both direct and indirect effects on their well being. Light pollution affects the timing of some songbirds singing, lessens birds’ sleep time, and changes the timing of migration when light pollution is present at overwintering sites. Light pollution affects birds indirectly through the effects it has on their insect food: light pollution affects insects’ reproduction, larval development, and adult behaviors. Maybe you’ve noticed a multitude of moths congregating around a streetlight? This nighttime distraction may be keeping moths from carrying out important behaviors, like mating and feeding. 

A swarm of insects surround a street light at night. This form of light pollution may have deleterious effects on the insects. Photo credit: © User:Lamiot / Wikimedia Commons / CC-BY-SA-3.0

Our part to play

There is a lot that we, as individuals, can do to reduce our light pollution impact. A good motto is only light if, when, and where needed. 

• If: Evaluate the necessity of your outdoor lights. For wildlife, less is best!
• When: Consider putting your lights on a timer or a motion sensor. 
• Where: For any lights that you do have outdoors, shield them and direct them down. Curtains and blinds reduce the light trespass from indoor lights. 
• Wildlife is most affected by white and blue toned lights, so consider switching your bulbs to warmer colors. 

There is a lot that individuals can do to reduce their light pollution, but light pollution is a communal problem! Have you ever noticed the level of light pollution where you live? You can check out the level of light pollution in your community using this interactive map. Advocating for a community lighting ordinance is an impactful way to reduce light pollution where you live. 

If you’d like to learn more, check out the national Audubon Society’s Lights Out program and the Michigan Audubon’s Safe Passage Great Lakes program. 

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Alice Dykstra is a doctoral candidate in the Haddad Lab at the Kellogg Biological Station and a Science Education and Outreach fellow for the 2023-2024 academic year.