NATURAL EVENTS

 

by Jack MacRae

Here’s what’s debuting on nature’s stage in Chicago Wilderness

Early Spring

Leopard Eyes

Next time you have the opportunity, be sure to gaze into the beautiful eyes of a northern leopard frog. Its irises have two layers of pigment and appear as a warm shade of liquid brown flecked with gold. Northern leopard frogs are common in protected wet areas and will do most of their breeding in April. The male will call (described as a throaty, low-pitched snore), its thumbs will swell, and the female will respond. She will lay a mass of eggs close to the water surface in sunny spots amongst the emergent vegetation. Northern leopard frogs don’t have the powerful mating call of the bullfrog, although they do give a loud squeak when frightened.

Under the Bridge

Eastern phoebes are among the earliest of the spring migrants to return to the Chicago Wilderness. The phoebes that nest under a footbridge near my office arrive in early April. They’re conspicuous and put on quite a show as they fly out from a perch to grab big flying bugs from midair. They have stiff bristles around their beak that help funnel prey into their mouth. On quiet mornings you can hear them snap their beak shut. While most young songbirds need to hear adults singing before they can learn their song, researchers have proven that phoebes know their familiar two-note song innately. Phoebes are able to sing fee bee perfectly, even when raised in isolation from other phoebes.

Middle Spring

Easter Vulture

Without a doubt, turkey vultures are our largest cavity-nesting bird. And it takes a big tree to have a hole large enough to hold a vulture nest. Snapped and split oaks seem to be the tree of choice. While spending their Easter Sunday playing in the woods and climbing logs in Raccoon Grove, a local wildlife veterinarian and her husband discovered one occupied nest jammed inside a broken oak trunk. The irate, hissing adult bird filled the entire cavity; its big red feet were visible through a fissure in the trunk. Four years ago, another pair of turkey vultures raised their young in the hollow base of a cracked tree in the Sag Valley Preserve.

Solar Powered

Just as the ground temperature approaches the air temperature (or just as the temperature six inches underground exceeds 50° F), our resident rattlesnakes will rise to the surface. This typically occurs in April, with final viper emergence often following three consecutive days of 60° weather and some warm rain that raises the water table. Massasauga rattlers slither slowly the first few mornings of the new season; they need a good jolt of sunlight to kick-start the production of vitamin D3 in their skin cells. They can be spotted basking in the warm ultraviolet light of the mid-morning sun. Once sufficiently charged, they retreat under cover and rely on cryptic coloration to stay out of sight.

Late Spring

Ants & Wildflowers

The study of “myrmecochory” investigates the highly complex and mighty mysterious mutualistic animal and plant relation-ship of ants dispersing seeds. In our little corner of the world, many of our spring ephemeral wildflowers, including wild ginger, bloodroot, violets, and trillium, grow from seeds transported by ants. The ant collects seeds by mouth and carries them back to their nest for a snack. After consuming a nutritious portion of the seed — but leaving the hard coating intact — the ants discard the seeds in a heap where they’ll often grow. Some bloodroot researchers believe seed germination occurs more quickly due to the ants’ activities.

Mellow Yellow

Don’t tiptoe through the marsh marigolds. These lovely flowers (ruffled, heart-shaped green leaves with five to seven brilliant glossy yellow sepals) can cause a nasty case of dermatitis. Confusingly, they are not marigolds, but members of the buttercup family. A plant of the northlands, they thrive in calcium-rich areas. I have found awesome colonies of marsh marigolds growing in the shady areas next to the West Branch of the DuPage River, where they thrive in the water that has seeped through limestone.