Written by ABNC Volunteer Alyssa Goforth

What is Firefly Watch?

*Firefly, likely Photuris versicolor. Note the midline stripe on the wing covers.*

Starting this year, ABNC volunteers have been participating in a community science project called Firefly Watch! We also have some outside volunteers who are Texas Master Naturalists. Massachusetts Audubon and researchers at Tufts University teamed up for the project with the goal of learning how firefly populations are distributed around North America and how the populations might be changing, in numbers and geographically. Using data collected by citizen scientists across the continent, they learn about what environmental factors are affecting firefly populations. Volunteers and staff have long wanted to do a survey of our native firefly populations, so joining Mass Audubon’s Firefly Watch was an easy decision to make. Learning more about our local native fireflies will help us to protect them and make our firefly hikes even better for our guests. A big plus for volunteers is that it is fascinating and fun! Hiking around ABNC in the dark is enlightening.

*Likely Photuris frontalis. Smaller than P. versicolor, and no midline stripe.*

What We Have Seen and Learned

We have seen fireflies in the forest, in wetland areas, and in the fields and prairies. When and where we see them has varied over time and with the weather. Based on their flash patterns and colors and also on the several specimens that we have photographed, we have seen species of fireflies from each of the three main groups of flashing fireflies: Pyractomena, Photinus, and Photuris. We saw Pyractomena in the woods in late March. In April and May, we saw what were most likely Photuris around the sugar cane field. In May we saw Photinus and Photuris in the woods along the Ladybird trail, and Photuris in the woods along the boardwalk and around the rotary pond. Later in May, after a nice rain, there was a wondrous explosion of activity and various fireflies were spotted in the area back of the pond across from the maintenance road and in the Grimes prairie. In June it varied. Earlier in the month there were very few, but then in mid-June we saw fireflies along the boardwalk, at the rotary pond, many in the woods, a few in the prairie, and around the fence near the parking lot. The next week, only a very few were spotted. Firefly numbers typically decline in our area by July, and an especially hot, dry June could speed the decline.

We have learned that fireflies are sparse on windy days, and that the dry weather probably has a lot to do with the scarcity of fireflies in the prairie. There seems to be a pretty durable firefly hotspot in the woods along the Ladybird trail short loop, especially around the bend that leads to the prairie. It is a beautiful place to stop and soak in the wonder. Although we have not noticed a correlation with the phase of the moon in our firefly data, it is striking how different the forest looks with bright moonlight and shadows compared to darker moonless nights.

We have learned that it is not so easy to identify fireflies to the level of species! The flash patterns and colors can be a great identifier of genus, and sometimes species. For instance, Photinus pyralis has a single flash pattern in the shape of a “J” with several seconds between flashes. In other cases, even with flash patterns and specimens, it can be tough to determine species. Certain attributes can narrow it down to genus, like the light stripe running down the midline of the wing covers of some species in the genus Photuris. We are learning that we have a lot to learn, and it has been a wonderful experience so far. We have had great camaraderie with our teams hiking along in the dark together, dodging spider webs, and wrangling fireflies here and there with our nets. Watching fireflies really is magical.

For more info on Firefly Watch and fireflies:

https://www.massaudubon.org/get-involved/community-science/firefly-watch