Many of our older guests at the Detroit Zoo and Belle Isle Nature Center can likely remember a time when they looked up and saw a sea of stars peppered across the night sky, clear enough to count the constellations.

Today, things are different. As populations and industry have grown, artificial light has seeped into our night sky to the point where many of the younger generation have never seen a truly dark sky.

This month, the Detroit Zoological Society (DZS) is raising awareness around this unfortunate phenomenon by helping our guests understand how they can protect our naturally dark night skies — and, in turn, help the animals we all know and love.

April 22-30 is International Dark Sky Week hosted by the International Dark-Sky Association (IDA). The IDA’s main goal is to fight against light pollution, which is the inappropriate or excessive use of artificial light. Research from the IDA and other institutions indicates light pollution can have serious environmental consequences for wildlife, the climate and human health.

How does light pollution harm your favorite animals?

Some of the most devastating impacts of light pollution have been to animals and their habitats. For an example, look no further than sea turtles. Though this species lives in the ocean, sea turtles hatch at night on the beach, with hatchlings finding their way to the water by detecting the bright horizon over the ocean. Artificial lights have been known to confuse hatchlings and draw them away from the water and away from survival. In the U.S. alone, millions of sea turtles die this way each year.

Closer to home, light pollution can have a harmful effect on bird populations. Birds who hunt or migrate at night use light from the moon and stars to guide their way. Artificial lights cause these birds to wander off course and into cities, where they are met with dangerous terrain. Once attracted to illuminated areas, birds collide with the glass of needlessly lit buildings and towers. According to the IDA, millions of birds die this way each year. Additionally, migratory birds depend on cues from properly timed seasonal schedules. Light pollution can cause these birds to migrate too early or too late and miss ideal climate conditions for nesting, foraging and other behaviors.

Outside of these two species, the effect of light pollution on wildlife can be subtler but no less harmful. Nocturnal animals have had their nighttime environments radically altered by light pollution, taking away the darkness prey species use for protection and confusing animals such as frogs and toads, who use nighttime croaking as part of their breeding rituals.

Artificial lights have been shown to disrupt normal nocturnal behaviors, causing inference with breeding and decreasing animal populations, according to the IDA. The worst part? Researchers are only just beginning to understand the ways light pollution has harmed animals and their environments.

What is the Detroit Zoological Society (DZS) doing about light pollution?

DZS and Belle Isle Nature Center staff strongly believe in the importance of nurturing, celebrating and protecting the night sky everywhere. While Belle Isle will likely never be fully dark due to its proximity to the city, we do everything we can to preserve the island’s nighttime darkness and protect local wildlife.

The DZS is a partner with the Metro Detroit Nature Network, now known as SEMI Wild, which in 2017 signed the Urban Conservation Treaty for Migratory Birds, designating Metro Detroit an Urban Bird Treaty area. Among other things, the treaty promotes bird conservation through Lights Out programs. These programs, of which we are enthusiastic supporters, implement dark sky policies encouraging organizations and individuals to turn off or reduce interior and exterior lights during spring and fall migration to help provide safe passage to migratory birds — potentially saving the lives of thousands of our feathered friends in the Detroit area each year.

Another way we continue to protect dark skies is through community education and promoting programs that educate the public about the natural night sky and what the average person can do to fight light pollution.

This International Dark Sky Week, tune into the Detroit Zoo Facebook page to see multiple posts about dark skies, their connection to wildlife and how the DZS is celebrating the week.

You can also join us from 8:30 to 10:30 p.m. Saturday, May 7 for Statewide Astronomy Night. The Wayne State University Planetarium at the Belle Isle Nature Center will be hosting a free, outdoor-only event, where guests can observe the night sky through a variety of telescopes and binoculars. Wayne State presenters will also be on hand to offer tours of the constellations and conduct exciting demonstrations. The Nature Center will also host an installment of its Nature at Night series, where you can learn all about how local nocturnal animals navigate a nighttime world.

What can you do to fight light pollution?

While the problem of light pollution can seem insurmountable, every little action taken can make a big difference. Here are three things you can do at home and in your community to support naturally dark skies:

• Eliminate unnecessary indoor lighting. Unused lights — particularly in empty office buildings at night – should be turned off.

• Make the switch to shielded outdoor lighting. Outdoor lighting should be shielded and directed downward, where it can illuminate the ground rather than contaminate the night sky.

• Research and spread the word! Visit the IDA website to learn about light pollution and the organization’s efforts to preserve dark skies. Then become an advocate for them! Talk to your friends and family to raise awareness around light pollution and help them understand why they should make changes to protect the night sky.

If we all take steps to reduce light pollution in our own homes and neighborhoods, there is a chance that one day future generations — and their furriest friends — will be able to look up and lose count of the stars scattered across the dark night sky.

– Amy Greene is the nature centers director for the DZS.