Counting butterflies: Volunteers step into nature to monitor populations

It  was 9:30 a.m. at the Corkscrew Swamp Sanctuary and a trio of women stepped carefully along the wooden boardwalk, watching the sea of plants and trees. 

Within five minutes on the trail, a fluttering orange-winged insect skimmed the edge of plants in the water and caught the eye of Becky Troop, a Corkscrew volunteer. 

Troop and her teammates Sally Stein, director of public programs at Corkscrew in Collier County, and Amy Swanson, a boardwalk naturalist, used a colorful field guide to identify the tiny orange butterfly as a least skipper.

"Gold star for me," Troop said. It was their first butterfly of the day.

Stein, Swanson and Troop participated in Corkscrew Swamp Sanctuary's annual July butterfly count Tuesday for the North American Butterfly Association. In its 19th year, the summer count at Corkscrew is an outlet for nature lovers, but it also serves a greater purpose — to understand what is happening to butterflies in the area.

Every year, the summer butterfly counts help Corkscrew staff and volunteers identify 20 to 51 butterfly species around the 15-mile in diameter count circle, where volunteers spend the day searching for butterflies. The sanctuary keeps a copy of the data for its own records and sends information to NABA. 

The data from the summer count, along with a second count in the fall, can identify problems with butterflies and their closely-connected host plants. For example, Stein said butterflies in the milkweed family have dropped significantly over the years at Corkscrew. 

"That's an indication that something is going on with their host plant," she said. 

On Tuesday, 17 people from South and Central Florida visited Corkscrew to participate in the annual summer count. The participants split into five teams to cover different areas within the count circle. Stein, Swanson and Troop made up the boardwalk team, which covered the 2½ mile wooden path, the insect trail and the parking lot.

As Stein, Swanson and Troop made their way along the boardwalk, they stopped every so often at different host plants, like Thalia geniculata, or the alligator flag, which is the host plant for the Brazilian skipper butterfly. They also paused at open, sunny clearings dotted with flowers. 

"The warmer it is, the more active you see the butterflies," Stein explained. 

Butterflies were fairly scarce in the early morning on the boardwalk, but then the trio reached the Corkscrew observation deck. 

As Stein, Swanson and Troop looked over the swamp from the tall wooden platform, something immediately caught their eye — a viceroy butterfly. 

Suddenly they spotted viceroys everywhere. The orange and black-striped butterflies flew in groups of two or three over the trees.

"There goes a palamedes swallowtail," Swanson exclaimed as another butterfly floated over the greenery. 

Swanson's interest in butterflies came naturally as a boardwalk naturalist at Corkscrew. She has participated in five summer and fall counts, but to get started, she picked up a guide to Southwest Florida butterflies at the sanctuary's gift shop and began to learn about different species. 

"I’ll take that with me when I’m at a doctor appointment," she said. "Sometimes when my husband and I are going for a long car ride I will grab the guide and study them."

Tuesday was the first butterfly count for Troop, who recently retired and began volunteering at Corkscrew this year.

Although she has visited the sanctuary many times, this year she began taking Florida master naturalist classes and other workshops to educate herself about the plants, animals and insects at Corkscrew. 

"I’m a generalist, so even though we’re out there looking at butterflies, I’m seeing other things like tree frogs, spiders and a few birds here and there. It’s a total immersion into an environment," Troop said. 

Stein has led the summer butterfly counts for about seven years and said she always learns something new.

"It's very important as far as biodiversity. You never know how something is going to affect something else and how it's linked together," Stein said. 

This year the July butterfly count identified 34 butterfly species and five of them — orange sulphur, little metalmark, ceranus blue, soldier and the twin-spot skipper — were species the count didn't find last year. 

Stein will send Tuesday's butterfly numbers to the NABA, which will combine the information with other counts across North America. 

"We just don't know what the future holds, so it's important to keep track of what's happening with nature," Stein said.