Post by Jen Berlinghof

As our hike continued south along the Des Plaines River Trail, we began to see, feel and hear the palpable signs of the seasons shifting from summer to autumn. We were not the only ones heading south along this greenway. Small flocks of Swainson’s thrushes and yellow-rumped warblers created a ruckus of fluttering feathers in search of sustenance.

Fall fruit, such as this highbush cranberry, provides a much-needed boost of energy for these birds, as they prepare for the long migrations that lie ahead of them. Caterpillars of countless moths eat leaves of this plant as well, fattening up for a cold winter spent in suspended animation either as larvae or pupae.

After eating its fill of a variety of green vegetation, this “wooly bear” caterpillar creeps across the trail, searching for a safe place under bark or inside the dark, protected cavities of rocks or logs to hibernate. While folklore tells us that the length and severity of the coming winter can be predicted using the length of this larva’s colored bands, science tells us that the burnt-orange central bands simply lengthen as the caterpillar ages. Once spring arrives, this caterpillar will crawl again and will quickly find a place to create a cocoon and pupate into an Isabella tiger moth.

Other insects were searching out hiding spots as well. We found small black beetles and the polka-dotted caterpillars of carrot seed moths tucked deep inside the Velcro-like seeds of the browning Queen Anne’s lace that lines the trail’s edge.

Bright yellow shafts of goldenrod dominated the landscape along the trail this season. Upon closer investigation, they, too, provide a winter haven for insects.

The bump seen on the goldenrod plant below is a called a gall. It began forming last spring when a female goldenrod gall fly (Eurosta solidaginis) deposited eggs on the tender shoot of the young plant. Over the summer, as the tiny larvae within ate and grew, the gall grew as well, swelling to a one-inch diameter. This fall, each plump larvae will chew a tunnel up to the gall wall, leaving a thin skin of plant tissue as a “door.” This tunnel will act as an escape route next spring when the fly has pupated and emerges as an adult.

We’ve also watched the milkweeds morph through the months—from the blooms of summer to the dried seedpods of fall, bursting with fluffy, floating seeds.

Milkweed seeds use the wind for dispersal, while the seeds of jewelweed seen below use mechanical ejection, literally jumping off the plant when an animal (or human hand) sweeps past the plant.

A fall hike wouldn’t be complete without fungus sightings. We watched as a pack of slugs gorged themselves on this giant puffball mushroom. Some puffballs can reach the size of a soccer ball and weigh up to 25 pounds. While it might be tempting to take home fungi found in the preserves, please remember that picking and collecting is not allowed in the Lake County Forest Preserves.

As we wound south through the open oak woodlands, we got, quite possibly, our last look of the season at the cerulean blue of a male eastern bluebird. A group of bluebirds was dashing this way and that in the skeletal branches of a cottonwood tree before heading out of town.

Yet, while the flashy colors of summer birds and flowers ebb, the striking colors of autumnal fungi and leaves begin to flow. Now is the time to get out and enjoy it—colors are at their peak in the preserves now. Take the Hike Lake County Challenge before the end of November, or traverse the full Des Plaines River Trail, which is officially complete.

Beginning today the final section of the Des Plaines River Trail is now open to the public!!! Completing the last piece between Riverside Road and Estonian Lane in Lincolnshire fulfills a vision 54 years in the making for an unbroken greenway along the Des Plaines River. Fall is a great time for hiking and biking, so get out and enjoy this 31.4-mile uninterrupted north/south venture through Lake County.

We’re excited to complete our adventure in the coming months. We’re hoping for some gorgeous frosty scenes during our November morning hike.

Notes from our hike: