Seeking Synchronous Fireflies in Appalachian Hills

It was about 10:30 pm, the darkness so inky you couldn’t see your hand in front of your face. The leafy boughs of late-spring trees blocked even the starlight. My friend whispered, “Do you want to see the blue ghosts? They live near the cemetery up the trail.”

Wondering if I was ill-advised in doing so, I followed her, stumbling up the dirt path. Our flashlights, swathed in red cellophane, cast an eerie glow on the headstones—many over 100 years old, some more recent. After reading the names on a few, I turned off my flashlight, stood rigidly still, and peered into the darkness. Slowly, as my eyes adjusted, I could discern several spectral, pale blue lights swaggering drunkenly at the edges of the graveyard.

In the Elkmont and Metcalf Bottoms area of the Great Smoky Mountains National Park, blue ghost fireflies (Phausis reticulata) are a counterpart to the famous synchronous fireflies (Photinus carolinus)  found there and in only a few other places on Earth. Though the Smoky Mountains are the most visited national park in the United States, few visitors have seen these ethereal insects. My knowledgeable friend was my guide to encountering them, and now, I share those secrets with you.

Finding Fireflies

Prior to 1991, locals knew about the synchronous firefly display, but science held that “there were no synchronous fireflies in the western hemisphere.” That’s when citizen scientist Lynn Faust contacted the experts mentioned in a Science News article on Asian synchronous fireflies. Field studies confirmed that the Elkmont fireflies were indeed synchronous, and since then, pockets of synchronous fireflies have been discovered in several North American parks.

In 2010, as a teenager, I excitedly waited with my parents at the Sugarlands Visitor Center for the buses to shuttle excited viewers to the Little River Trail parking area. We hiked with our flashlights a quarter of a mile up the trail, saw a few fireflies, and shuttled back.

This time, I leaned into the experience of a friend who had been viewing the fireflies for years. We spent our first evening of viewing, described above, on Jakes Creek Trail. Barely discernible between two boulders at the edge of Elkmont Campground Road N is a path to the trail. If you didn’t know it was there, it could easily be missed. Far from roads and parking lots, this trail offers near-complete darkness and access to the historic Levi-Trentham Cemetery. You can view the fireflies directly from the trail, facing into the woods, or enter one of the clearings with historic “ruins.”

The next evening, we stationed ourselves along the Little River Trail, where there are plenty of boulders for resting on and the foundations of long-lost buildings to explore.

In both settings, our view of the fireflies was fantastic, even though the predicted peak was still six days away.

What Does Synchrony Look Like?

Before our trip, I remember my husband describing what he expected to see: “They’ll all flash at the same time and light up a whole tree!” This misconception was likely due to time-lapse photographs in which fireflies seem to light up the forest. The camera uses a long exposure to capture much more light than can be seen in a single moment. It’s a representative image but not true to life.

The reality is much different but no less magical. Ten to fifteen minutes after dark, we began seeing a few flashes, but they weren’t synchronized yet. It was similar to what you’d expect to see in your own backyard.

After half an hour, more fireflies were active. Some—the females—flashed from the ground. The flying males began to synchronize. Most would flash six to eight times, then “turn off” for about six seconds. This is known as a flash-train. Every single flash wasn’t in synchrony; instead, there were periods with lots of flashing, followed by periods with none.

About an hour after dark, things got really interesting. Hundreds of fireflies were visible. Watching a wide swath of forest, I could see synchrony begin at one point and move outward like a wave. Scientists aren’t sure how the fireflies synchronize their flashes, but this display would suggest they do so visually. Sometimes, synchrony would begin at more than one spot—in front of you and behind you, for example, and the waves of flashes would appear to crash into each other. At other times, you could follow the wave of flashes by turning yourself in a circle.

Synchronous Fireflies in Elkmont Campground Photo: Shutterstock

A Mesmerizing Display

The display was mesmerizing. I felt as if I were on the fringes of something sacred and incomprehensible. Similar feelings, no doubt, gave rise to the ancient mythologies concerning fireflies on at least four continents. Occasionally, we’d notice a lone blue ghost firefly weaving its way through the others, its cold blue light remaining on for ten seconds at a time instead of flashing. It seemed to me like the one child in a ballet recital who spins in the wrong direction.

Here, I’ve described what synchrony looks like, but would you like to see it? Unfortunately, I can’t show it to you. The photos and videos I took scarcely captured the reality of the phenomena, what my eyes, sensitized to the darkness, could take in, and how it made me feel.

I’ve since scoured the internet for good videos of the fireflies. This clip from CBS Sunday Morning is the best one I’ve come across, but it is still a pale shadow of what it’s like to see synchrony with your own eyes. Maybe that’s what makes the Smoky Mountain fireflies so special—you have to see them yourself to truly appreciate them. The following tips will help you plan a successful trip.

Tips for Viewing Synchronous Fireflies

Fireflies’ nighttime displays occur for only a few weeks each year. The flashing is a mating ritual or “reproductive display.” If interrupted, it could imperil the next generation of fireflies. Not to mention the fact that you can literally step on the beetles hiding in the grass.

Huge interest in the insects brought record crowds, and in 2006, the National Park Service (NPS) began regulating the number of visitors during peak firefly mating season via a lottery system for obtaining parking passes. Winning the lottery can be a gamble, but you can still plan a successful firefly-viewing trip.

Firefly Viewing Tips

• Come before or after the peak.

  Passes are awarded via the lottery system during the 8-day projected peak of firefly activity. However, this peak time is only an estimate and can be affected by the weather, especially the temperature. Typically, fireflies can be observed successfully one week before and one week after this regulated peak period.

• Make your reservations early.

  Reserving a spot in the Elkmont campground puts you within walking distance of the fireflies and negates the need for a parking pass since you can park at your campsite. Reservations can be made up to six months in advance and often fill up quickly, especially around the firefly season. I recommend making campsite reservations that begin during the last week of May and continue a few days into June. These can be made as soon as May dates become available, a month before June-only reservations.

• Bring a red flashlight.

  Red light, unlike an ordinary white-light flashlight, won’t affect your vision once your eyes have adjusted. It’s also less disruptive to your fellow viewers and the fireflies themselves. Some headlamps and lanterns come with a red option, but you can also make your own—save the red cellophane from that heart-shaped box of candy in February and rubber band it over the end of your flashlight.

• Consider the moon.

  You don’t realize the amount of light produced by a full moon until you’re standing on an otherwise dark trail. If possible, plan your firefly viewing for nights when the moon is at a quarter or less.

• Find a spot before dark.

  Explore potential viewing locations by daylight. Then, hike there before it gets dark. This way, you won’t be stumbling over other viewers.

• Bring a chair.

  Those who are disappointed by the fireflies are usually the ones who spend only a few minutes viewing them before heading back to their campsite or the nearest restaurant. Scout out a big, flat rock along the trail, or pack a lightweight camp chair. You should plan to stay for at least an hour after the sky is fully dark to allow the fireflies to really get going.

• Enjoy the moment.

  As mentioned above, photographing the display is nearly impossible. Instead of interrupting your adjusted eyesight with the light from your smartphone, simply look around and enjoy the moment. Unlike so many travel experiences, the synchronous fireflies aren’t well suited to Instagram. Instead, they’re something you need to experience in real-time.

Note: The Elkmont Campground is located in the region recently affected by Hurricane Helene. The campground is open to visitors, but road and park closures are still in effect nearby. Please exercise caution and compassion in visiting as the area heals from this devastating disaster.

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