As nights grow longer, keep the stars bright by cutting down on light pollution at home

As summer gives way to fall, the days are growing shorter and the nights are growing longer. Most of us respond by flipping on more lights around our homes as a logical modern solution. And while it may feel cozy to brighten the darkening evenings, excessive or poorly placed outdoor lighting creates a growing environmental issue: light pollution.

Light pollution is when artificial light spills beyond where it is needed, brightening the local environment and the night sky. The pollution aspect of this comes from how it alters these natural spaces. According to the International Dark-Sky Association, it disrupts natural cycles for humans and wildlife, obscures our view of the stars, and wastes billions of dollars in energy every year.

Wildlife in the Rocky Mountains depends on natural darkness to survive. Here in the Eagle River Valley, artificial light acts as a repellent for elk, reducing their ability to coexist with us in more densely populated areas. Rodents also shy away from artificial light, making it hard for nocturnal predators like great-horned owls to sustain themselves in well-lit areas.

Another large mammal that is quintessential to life here in Colorado, the mule deer, is drawn to artificial light, which increases the risk for road accidents. Mountain lions rely on stealth, so the illumination around human development greatly reduces their ability to hunt, inflating deer populations in more urban areas.

As you have probably seen on many occasions, little flying critters are attracted to artificial light too. When insects such as native bees and tiger moths flock to lights in the nighttime, a portion of their population often dies in large numbers, disrupting pollination and food chains. Little brown bats struggle to find sufficient food when insects disappear because of artificial light. Even migratory birds can be affected: White-crowned sparrows, American robins, and other songbirds use the stars to migrate; artificial light can disorient them, causing collisions and lost flocks.

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Wild animals aren’t the only ones affected, either. Exposure to light at night can interfere with our own circadian rhythms and melatonin production, making it harder to fall asleep and stay energized during the day. On top of that, every watt of wasted light adds to electricity bills and carbon emissions.

The good news is that small changes at home can make a big difference. Here are a few simple steps to get started:

1. Choose shielded fixtures. You probably already have this one down. We are a pretty environmentally conscious community, so most of the towns in the Eagle River Valley are Dark Sky Communities in which shielded fixtures — lights with covers that direct light downward, preventing wasted light from spilling into the sky or neighbors’ windows — are actually required.
2. Use motion sensors or timers. Lights don’t need to stay on all night. Installing sensors or timers ensures they’re only active when needed.
3. Select warm-colored bulbs. LEDs with a color temperature below 3000K reduce blue light, which is particularly disruptive to wildlife and human sleep.
4. Turn off decorative lighting. Strings of lights and bright landscape fixtures can add charm, but they’re not always needed. Consider saving them for special occasions.
5. Close curtains indoors. Even indoor light spilling outside contributes to neighborhood skyglow.

As the nights grow longer this fall, take a moment to look up. By reducing unnecessary light, you’ll protect wildlife, save energy, sleep better—and enjoy the simple pleasure of a star-filled sky.

Akani Bey is a naturalist at Walking Mountains. He aims to reawaken people’s connection with nature through his guided nature walks, backcountry hikes, and early childhood programming.