The Impact of Artificial Light on Nocturnal Wildlife

Discover how artificial light at night disrupts nocturnal wildlife—from sea turtles to birds—and learn simple ways we can reduce its ecological impact.

Written by Warrence Oghenevwegba

Published on: April 5, 2025, 3:09 P.M

When the sun sets and nature winds down for the night, another light—one not born of stars or fireflies—takes over the landscape. Streetlights, billboards, vehicle headlights, and glowing cityscapes brighten the night, not just for us, but for the countless creatures that depend on darkness for survival.

But what happens when night no longer feels like night?

Artificial light at night (ALAN) has become one of the most overlooked forms of pollution, subtly yet profoundly disrupting the rhythms of ecosystems around the world. While it may seem harmless to us, for many nocturnal species, this intrusion of brightness is a source of stress, disorientation, and in some cases, mortality.

Nocturnal wildlife—animals that thrive in darkness—have evolved behaviors, senses, and survival strategies finely tuned to natural light cycles. Owls rely on dim moonlight for silent hunting. Sea turtles hatch on moonlit beaches and navigate toward the ocean using the natural glow of the horizon. Fireflies signal mates using bioluminescence. Bats emerge under the cover of night to forage. Yet, all of these species are increasingly struggling in environments washed in human-made illumination.

Take sea turtles, for instance. Along coastlines where artificial lighting from hotels, streetlights, and homes spill onto the beach, hatchlings become disoriented. Instead of moving toward the sea, they're drawn inland toward the brighter lights—where they often perish from dehydration, predation, or traffic. Similarly, fireflies face difficulty in finding mates when competing with excessive outdoor lighting. Their soft flashes get drowned out in a world of glaring LED bulbs.

Birds, especially migratory species, are also severely impacted. Many birds navigate using celestial cues. When flying over brightly lit cities, they become confused, circling lights for hours, expending precious energy, and risking fatal collisions with buildings. One staggering estimate suggests that up to a billion birds die annually in North America alone due to collisions, with light pollution being a significant contributor.

The effects aren’t limited to just navigation and reproduction. Artificial light disrupts circadian rhythms—internal biological clocks that govern sleep, feeding, and other vital functions. For prey animals, exposure to constant light increases vulnerability to predators. For predators, it alters hunting success, often leading to imbalances in local food webs. Insect populations, already in decline due to habitat loss and pesticides, are further stressed by lights that attract and trap them in fatal loops around bulbs and signs.

The ecological consequences of these disruptions cascade through ecosystems. When insect populations decline, so do the birds and bats that rely on them. When turtle hatchlings die before reaching the ocean, marine food chains are affected. Light pollution, though subtle, acts like an invisible net, ensnaring one species after another in a chain reaction of imbalance.

So, how can we begin to restore the natural night?

Solutions exist, many of them simple and cost-effective. Shielded lighting, which directs light downward rather than outward or upward, reduces unnecessary spread. Motion sensors ensure lights are only on when needed. Warm-colored bulbs, as opposed to blue-rich LEDs, are less disruptive to wildlife. Urban planners and developers can incorporate “dark sky” principles into community designs—preserving darkness in key ecological zones. Some regions have even adopted "lights out" programs during bird migration seasons, encouraging buildings to turn off or dim lights during peak travel times.

On a personal level, individuals can take part by installing outdoor lights with timers, drawing curtains at night, or simply turning off unnecessary lights. While it might seem small, collective efforts add up.

In the age of rapid urbanization and 24/7 lifestyles, darkness has become an endangered resource. And yet, it’s one we can protect—if we choose to recognize its value not just for ourselves, but for the silent, shadowy creatures that depend on it.

Is it time we reimagine the night, not as a void to be filled with light, but as a vital part of our shared environment deserving of respect and preservation?

Let’s allow the stars to shine again—and give nocturnal wildlife back their night.