The din of the dog days

Post by Jen Berlinghof

The dog days of summer are a bounty for the senses. We see the lemon-yellow of whorled sunflower blooms, taste the ripe flavor of a homegrown tomato, smell the spicy sweetness of bee balm flowers, feel the heat of the day and the cool of the evening. Yet the most quintessential sensation of these end-of-summer days is hearing the overwhelming cacophony of cicada songs around the Lake County Forest Preserves in northern Illinois.

When we talk cicadas, the first questions that often come to mind concern periodical cicadas that emerge en masse every 17 years. This phenomenon is fascinating, but our last emergence of Magicicada occurred in 2007, so we will have to wait until 2024 to experience that spellbinding season again.

The cicadas we hear now, and indeed every summer, are considered annual cicadas. While their lifecycle actually lasts anywhere from two to five years, they’re not synchronized, so we end up hearing and seeing some each year.

Whether periodical or annual, all cicadas go through the same basic lifecycle. A female deposits rice-shaped eggs into grooves on small branches. She makes these grooves with her sharp ovipositor, a sword-like organ that extends from her abdomen for this purpose. Later, teeny cicada nymphs hatch out, then plummet to the ground and burrow in the soil in search of a root to feed on. They start with grass roots, and as they grow and molt, the nymphs eventually work their way up to a host tree root where they’ll sip away at sap for years.

When it’s time to emerge, cicada nymphs claw out of the dirt and head for higher ground to complete one final molt: shedding their exoskeltons. The exoskeletons, or what my kids always called “cicada coats,” remain on tree trunks and tall grasses long after the cicadas’ wings have inflated and they’ve flown away to complete their courtship and mating rituals.

The most obvious of those rituals is the mating songs of the male cicadas. These “true bugs” sing with their tymbal, an organ with a series of ribs that buckle when the cicada flexes its muscle. Like a bendy straw being pushed together and pulled apart, each snap of a rib collectively creates the loud, buzzing song.

And loud it is, sometimes reaching up to 100 decibels, the same intensity as a motorcycle rumbling past on a warm summer night. It may seem strange—and deafening—that a cicada sports exposed eardrums on its abdomen right next to the tymbal. But nature has figured out a workaround; just as male cicadas start to sing, a small muscle folds the eardrum shut.

You might have noticed the cicada chorus isn’t monotonous. It includes a variety of buzzing, clicking, and grinding noises. There are actually more than 190 species and subspecies of annual cicadas throughout North America. In Lake County, we commonly hear three species. The dog-day cicada (Neotibicen canicularis) sounds like a buzzsaw and tends to sing during the heat of the day. The scissor-grinder cicada (Neotibicen pruinosus) sings its grinding song from late morning until dusk. And Linne’s cicada (Neotibicen linnei) sounds like a whirring rattle all day long.

For better or worse, our eardrums don’t fold shut when cicada songs really get going. It’s worth keeping in mind, though, that what may seem like racket to us is sweet music to female cicadas’ ears. Enjoy the crescendo of the chorus in these dog days of summer.

The wonder of wood ducks

Post by Jen Berlinghof

Spring is the starting block for wildlife in the race to find suitable mates and nesting sites. With the increased flurry in wildlife activity, staff at the Lake County Forest Preserves in northern Illinois also get an increased flurry of phone calls with questions from the public. One recent call came from a gentleman in disbelief upon seeing ducks perched in his trees. He was utterly transfixed by the phenomenon. The call brought back a flash of memory for me of the first time I saw a wood duck (Aix sponsa) as a child, on my maternal grandfather’s property in northern Illinois. Grandpa “Duck,” as we affectionately called him, was an avid outdoorsman. He spent a few moments that spring day pointing out the distinct, vibrantly hued male and the more muted female near a nest hole in an old maple tree. The pair then took off into the woods to the soundtrack of their high-pitched whistling calls.

Male wood ducks are easily identifiable by their glossy green head, chestnut breast, and other vibrant colors. Stock photo © Lake County Forest Preserves.

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Goldenrod galls

September in Lake County, Illinois is a month of big sky punctuated by tips of tall prairie plants in an array of autumnal colors. Before the trees really get going with their own colorful show, sparks of bright yellow from the many varieties of goldenrod (Solidago spp.) dominate the open spaces. Most of the summer these plants go unnoticed, adding merely another green hue to the lush surroundings, but September is their time to shine. What may also go unnoticed, even now as goldenrod demands our attention, is the hidden world inside each plant in the form of a gall.

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A screech-owl’s story

Last week, many of us who work at the Lake County Forest Preserves had to say a sad goodbye. Our resident eastern screech-owl (Otus asio) passed away in the middle of the night. This male owl had spent the past seven years as an ambassador for the Lake County Forest Preserves, teaching thousands of people about the adaptations of raptors and owls. I have seen time and time again—from school children on education field trips to adults attending special events—a person’s eyes lock in and a look of amazement wash over them upon meeting this charismatic bird.

Sadly, his story is not uncommon. This particular bird was recovered in January 2004 as a juvenile. He was found by a concerned citizen in a driveway in Round Lake, Illinois with obvious head trauma and his left eye swollen and filled with blood. He was taken to Barnswallow, a raptor rehabilitation center in Wauconda, Illinois. It is suspected that this screech-owl was hit by a car, but he also had tiny sores on his talons and translucent, sheared tail feathers. These latter symptoms are signs of secondary viral infections caused by the West Nile Virus. After spending 16 months at the rehab facility, he was deemed unsuitable for release back into the wild due to the uncertainty of his eyesight in the injured eye. In the spring of 2005, he came to live in his very own mews (i.e. flight cage) near the farm area at Ryerson Woods. There he joined another resident bird, a red tailed-hawk (Buteo jamaicensis). Continue reading