Want to help wildlife? Turn off your lights

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Want to help wildlife? Turn off your lights. 
It’s not just about seeing the stars. Bright city lights disorient animals like birds, leading to fatal 
collisions and potential long-term damage to their health. 
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Look for a constellation in the glow of a city, and at best you might see a star or two. That’s 
because light pollution is turning night into day in 80 percent of the world. 
The day to night cycle is an essential part of nature, telling animals when to emerge to hunt, 
forage, migrate, and mate. When artificial light disrupts those natural light cues, wildlife from 
bugs to birds, and even plants, are seriously impacted. 
It’s a problem getting worse every year, but there are simple solutions to help wildlife and 
restore our night sky view, experts say. 
“When we look at the sky and we can’t see the stars, it’s a sign that our lighting is poorly 
designed and wasteful,” says Christopher Kyba, a physicist at the GFZ German Research Center 
for Geosciences. 
Some communities are rethinking rules for lighting at night, starting with simple changes to 
reduce light pollution coming from individual homes. 
How light pollution harms the environment 
A report from last year examined over 160 species of plants, fish, mammals, and insects to 
understand how our artificial lights are changing ecosystems. Researchers found that animals 
look to light via the rising and setting of the sun and moon to determine when to emerge from 
their hiding places to hunt, forage, migrate, and mate. All manner of wildlife is affected—for 
example, some bugs can be more easily preyed on and some birds fly off course. 
“For all of evolutionary history there was a stable pattern—any animal or plant can anticipate 
day and night,” says Kyba. “But when we add a bunch of artificial light, obviously that’s going to 
mess things up.”
Fireflies use light to signal to potential mates at night. But city and suburban lights outshine 
these cues at alarming rates. One study published in 2020 suggested light pollution, along with 
habitat loss and pesticide use, could put some of the world’s 2,000 different firefly species at 
risk of going extinct. 
Birds are also easily disoriented by bright city lights and frequently die from colliding into bright 
buildings reflecting the sun and shining artificial light at night. Even dim lighting far from the 
city may impact their health. 

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