Observing Fireflies

Firefly flashes in a field © Greg Saulmon
© Greg Saulmon

There are two ways to observe fireflies:

  • From afar by watching their flight paths and flash patterns.
  • Up close to determine what type and gender by examining body parts.

Observing From Afar

As you begin to observe the fireflies in your habitat, you will quickly notice that they have different flash patterns. Each species of firefly has its own pattern. Many fireflies look similar, so these flash patterns help to identify particular firefly species.

Firefly Flashes ID infographic
Click to enlarge

With a little practice, you can learn to recognize many fireflies by their flash pattern. This graphic can help >

If you hope to observe fireflies in action, be careful not to shine flashlights or other bright lights near them. Fireflies communicate using light, so bright lights can disrupt their communication, and interfere with their nightly routine!

You can protect fireflies and still safely see in the dark by using a red flashlight. You can turn any flashlight red by taping a few layers of red acetate (available at most art supply stores). Use this flashlight to get to your firefly habitat—but once you find fireflies, turn it off and let the insects take care of the lighting!

If you let your eyes adjust to the dark, their display will appear even more beautiful.

Note: Be on the lookout for ticks and wear insect repellent!

Up-Close Observation

There are three major kinds of flashing fireflies in North America, and you can tell them apart by looking closely. You can also tell the sex of a firefly by examining its brightly glowing lantern.

To do this, place the firefly so you can see the underside of its abdomen. The lantern covers the last one or two abdominal segments. Male lanterns are larger, covering two whole segments. Female lanterns are smaller, and cover just a small part of one or sometimes two segments.

The best way to observe a firefly up close is to capture it in a net, and place it gently into a clear box.

Report Your Sightings

Join a network of volunteers by observing your own backyard, and help scientists map fireflies found in New England and beyond as part of Firefly Watch. Learn more >

How to Catch a Firefly 

Catching fireflies is fun and a great way to observe them up close. To avoid harming a firefly, collect it with a net. Then gently place it in a jar containing a moist paper towel for humidity. After you’ve gotten a good look, remember to let your fireflies go where you found them.

If you handle fireflies, make sure you don’t have any insect repellent on your hands, and wash your hands carefully when you’re done.