HANCOCK TOWNSHIP - A brown splotch stained the green birch tree leaf that 11-year-old William Kotajarvi held in his left hand. It was a sign troublesome pests were lurking.
"See, they live inside the leaf," he said, holding the tattered specimen up to the sunlight to examine birch leafminer larvae tucked within its layers. "You can tell they're there because it's got the brown spots."
The Laurium youth was one of 16 curious adventures who engaged in a "Caterpillar Walk" at McLain State Park Wednesday. The hour-long adventure, which included a brief informational session followed by a hike in the woods, was a part of McLain State Park's Summer Explorer Program. Held throughout the week, the programs are open to campers and day visitors at no cost.
Daily Mining Gazette/Kelly Fosness
Six-year-old Elija Aylward of DeWitt, Mich., examines a birch tree leaf under a mini microscope at McLain State Park Wednesday.
"The purpose of the program is to familiarize people with nature," Explorer Guide Jennifer Kelby said. "It's tailored for both kids and adults and the topics are always changing."
Kelby said topics include forestry, astronomy, insects, night hikes, pond studies, agate identification and frog hunts, among many other family-friendly events.
"We also do a recycling program where we make bird feeders out of plastic bottles," she said.
Wednesday's caterpillar program got under way just before noon at the park's main picnic shelter where parents and children gathered to hear Kelby talk about the birch leafminer.
"This is a caterpillar we found on the tree hike yesterday," she said, while removing it from the clear plastic bug box. "I researched it and found out what it was."
Her microscope in tow, participants lined up to get an up-close look at the larva, while learning about its life cycle.
The birch leafminer, she said, is a small sawfly native of Europe. The adult sawfly is a small, 1/4-inch long, black, fly-like wasp.
"The small, white and slightly flattened larvae of the birch leafminer live within the birch leaves," she recited from her research. "They can be easily seen when the leaves are held up to the light."
From the picnic area, Kelby led participants, armed with mini microscopes, to a birch tree stand for a hands-on look at the particular caterpillar. For many, it was jaw-dropping, finding the small larvae hidden in between the top and bottom layers of the leaves.
A nature trail hike concluded the program Wednesday and along the way, Kelby reminded the group to pay attention for signs of caterpillars.
"If you see leaves partially eaten, there's a good chance you'll see one," she said.
Denise Landberg of Houghton, who was day-visiting the park with her two children, said the explorer program is a neat addition to the park.
"I think it's excellent - it gets the kids outside," she said.
Kotajarvi said his family was on a five-day camping trip at the park and Wednesday was his second day in a row participating in the explorer program.
"I did the tree hike yesterday," he said. "We learned the different parts of trees and then we took crayons and colored on paper over the leaf to get its pattern. It was a lot of fun."
While the programs are designed to be educational, Kelby also hopes they help participants develop an appreciation for nature.
"I just love the curiosity that the kids have," she said. "And, the adults too ... it really is designed for both."
Kelby said the explorer program at McLain State Park will continue through August.
For more information or for a schedule of events, call McLain State Park at 482-0278 or visit the Department of Natural Resources at michigan.gov/dnr.