Missoula butterfly counts provide environmental clues, nature education

The Rattlesnake Recreation Area pulses with an increasing number of hikers, runners and bikers. This week, they had to share the trails with one more group: butterfly counters.

Each summer in early July, a troop of amateur lepidopterists, armed with butterfly nets, observation boxes and identification guides, head up the Spring Gulch and Mainstem Rattlesnake trails to identify and count every butterfly they see.

On Thursday, that was a bit more fun than it’s been in years past.

“This is the best count we’ve had in a long time,” said volunteer count coordinator Kristi DuBois. “The weather’s been so weird. Last year was a bad year for insects in general. But this is more like the good old days.”

A dozen volunteers headed up the mainstem trail while Kristi led a group of eight up Spring Gulch. The event was originally scheduled to start at 10 a.m. because mornings are normally cool and butterflies need to warm up before they start moving around. But this season, with unseasonably warm temperatures dominating the area the past three weeks, DuBois pushed up the meeting time to 9 a.m.

Even then, butterflies were already out and about.

Nets angled through the air as people tried to snag wood nymph, brown crescent, sulphur and swallowtail butterflies.

Those that were caught were transferred to a mesh box for a more detailed identification. Was that a northern blue or a lupine blue butterfly?

One trend popped out as some butterflies were held side-by-side: several were smaller than others of the same species. DuBois said some size variation always exists. But it could indicate an environmental change, because size depends on the condition of the caterpillar before it became the butterfly. Maybe many of the blue butterflies were “runt-y” because their caterpillars didn’t get enough to eat.

That’s part of the reason why the North American Butterfly Association sponsors nationwide butterfly counts: long-term data collections can identify population shifts, which can indicate changes in the environment, including those related to climate change.

For example, volunteers counted 400 blues alone in some years, while during the past few years, they counted only 400 butterflies total. This year, the drought may decrease the butterfly populations in places like Helena where fewer wildflowers are blooming.

The count in the Rattlesnake has been going for about 26 years, started by Will Kerling. DuBois took over about 14 years ago and said different species’ populations can go up and down over time. But she can point to one change in particular that could affect butterflies.

“I don’t know if it depends on the plant species that they eat, or something else. Some of them have different wintering strategies, which could affect them in different years, and fall and spring freezes can play a part” DuBois said. “But the meadows are filling in with trees. (The meadows) not as big as they used to be. And I think that’s a factor.”

Right now, the meadows are filled with daisies and other wildflowers that butterflies and other insects use for food. But smaller meadows mean fewer flowers.

One other count site is east of Florence on the MPG Ranch. Marirose Kuhlman has led that count since 2013 and agreed this year was a good year. At one point during their count on Tuesday, they were surrounded by so many butterflies that one volunteer said people could almost just stand with their nets open and butterflies would fly in.

As with Audubon’s Christmas bird count, another reason to hold counting events is for education. The people participating in the counts learn to identify butterflies that live in their area. The hope is the more people appreciate butterflies, the more they’ll want to save them. That’s reflected in the North American Butterfly Association motto: “If we can save the butterflies, we can save ourselves.”

Volunteer Sally Friou enjoys participating in the count since she retired a few years ago.

“It’s such a delightful way to spend a day,” Friou said watching a swallowtail flit overhead. “Butterflies are so magical. And you get to hang out with like-minded people.”

Some people become so enraptured that they do more than one count. A couple from Indiana attended the MPG count, and Kuhlman learned they were traveling the country to join in as many butterfly counts as they could.

DuBois is just as passionate but this will probably be her last year coordinating the count. But she said she’ll still come out for the count to see which way the trends go next.

Contact reporter Laura Lundquist at lundquist@missoulacurrent.com.