Late last summer, I literally watched a groundhog (Marmota monax) fatten up before my eyes. He’d made a burrow in the field outside my office window and frequently visited the rain gardens around the Edward L. Ryerson Welcome Center in Riverwoods, part of the Lake County Forest Preserves in northern Illinois. We watched him scamper back and forth, snipping flower tops here and there, always with a mouth crammed full of flora.
Fast forward to early February, and as I look out across the same field, now dotted with small snow drifts punctuated by tufts of grasses gone tawny, I think about that groundhog curled tight in his burrow and deep in hibernation, oblivious to the hubbub of a day in his honor.
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.
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.
This winter has been harsh in Lake County, Illinois, causing many of us to wish we could migrate to South America like some birds do, or hibernate in a cozy underground den like the groundhog. Alas, most of us just stick it out in the cold. It may offer consolation to know we are not the only animals active during these record-breaking cold, snowy days. It turns out there is a whole ecosystem teeming with life right under the snow.
Recently, scientists having been taking a closer look at life in the subnivean, which literally translates to “a place under the snow.” The space between the snow and the ground acts as a seasonal refuge for invertebrates, birds, and small mammals. Snow affords these small critters with remarkable insulation, and temperatures around 32 F regardless of the temperature above the snow. Biologist Bernd Heinrich explains the science underlying these insulating properties in the book Winter World: The Ingenuity of Animal Survival. “As long as both ice and water exist side by side, they constitute a thermostat keeping temperatures constant.” When water converts to ice crystals, heat releases. When ice turns into water, the process uses up heat.
Many years ago, while running along the Lake Michigan shoreline late on an evening in January, a feathered ghost appeared on top of a flag pole. It was the first time I had ever seen a snowy owl (Bubo scandiacus) and it stopped me in my tracks. This was the spark on that frozen night that lighted my fire of curiosity about birds. This winter, snowy owls have left their Arctic homes in record numbers, causing one of the largest irruptions (sudden increase) in northern Illinois in decades.
Although it seems natural to correlate the arrival of these boreal birds with the extremely cold, snowy winter northern Illinois is having, experts say the motivator is more likely linked to food. On their Arctic breeding grounds, snowy owls feast under 24-hour sunshine. Their food of choice is lemmings, small mammals with an extremely cyclical population. Bird expert Kenn Kaufman explains in a recent Audubon magazine article, that when the lemming population explodes, like it did last summer in northern Quebec, snowy owls have great breeding success, producing large broods of up to 11 chicks. As these chicks quickly grow into juvenile birds, the competition grows for the now dwindling numbers of lemmings. Thus, the young birds get nudged further and further away to find a meal, resulting in them moving to areas that mimic their treeless tundra home, such as the Lake Michigan shoreline. Continue reading →
Leaves throughout the forest glowed gold against a backdrop of graying sky as I left Ryerson Conservation Area yesterday afternoon. This morning—as I entered the same preserve along the same road—the dark, skeletal branches were completely visible, stripped of their vibrant leaves that now lay in muddied piles on the forest floor.
These days of November mark a change from crisp colors to muted tones, which offer the perfect backdrop for animals to hide using camouflage. Lake County Forest Preserve educators often teach the concept of camouflage during environmental programs, where students hike in search of animal hides and mounts that have been hidden along the trail. Teachers and scout leaders, peruse our variety of school and scout programs to find a great fit for your group this year. Following is a virtual version of our camouflage hike. Continue reading →