Natural Events

by Jack MacRae

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

Early Fall

Willowy

Willow Aster sounds like the name of a Hollywood starlet who pals with Paris or Britney. And while she may not bloom for more than a few weeks in September, willow aster's career as a perennial wildflower is solid. She does her best work in moist, fertile, black soils with full sunlight. The flowers of willow aster resemble small, light blue daisies. They attain their name from the long thin (willow-like) leaves with a distinctive network of veins visible on the underside. Willow aster stems have a red tinge to them.

Peace Wasp

Organ pipe mud daubers, a common type of solitary wasp, are peace-loving parents that construct totally tubular homes of natural materials to protect their eggs. Then in a wicked, Tarantino-esque twist, the female wasp attacks some large garden spiders and paralyzes them with a venomous bite. She then stuffs the un-dead arachnids into the sealed chamber for her offspring to consume upon hatching. These nesting chambers are quite common. Look for light gray tubes, four to six inches long, adhering to the walls of our old structures in public parks and preserved areas. Each of these tubes may contain six or more zombie spiders.

Middle Fall

Big Black

During a typical election season, when our politicians are pleading their cause, our crows can be heard cawing their pleas. Bird observers have noted that crows are considerably more vocal during fall, with much of the communication occurring between young flyers still developing the social skills necessary to be an au courant crow. In October and November, crows of all generations will start to roost communally in the branches of mature trees. These roosts grow larger as the weeks pass. Many Chicago Wilderness communities contain caucusing crows.

Velvet Underground

Mourning cloaks are out and about long after most butterflies have stopped fluttering for the season. They get much of their nourishment from decomposing fruit, which is still available later in the fall than most flower blossoms. As the temperature falls throughout October and November, mourning cloaks will internally begin production of a natural antifreeze, a chemical cocktail of alcohols and sugars that inhibits the creation of ice crystals in the insect's tissue. These elegant beauties, with dark, velvet-like wings, will slip into a protected tree bark crevice to escape the harsh elements of winter.

Late Fall

Bonaparte's Gull

Some gulls rarely scavenge. Bonaparte's gull is a graceful little gull with a dainty black bill. At a little over 12 inches--only half the size of a herring gull--they are the smallest North American gull. They breed in the remote parts of boreal forests of Canada where, in very un-gull-like manner, they build their nests in trees. At the end of the summer breeding season, Bonaparte's gulls disperse south, east, and west, where they look for large lakes to float away the winter. Inevitably, some intrepid gull trippers end up in Chicago Wilderness. According to the records, November is the month they seem to be seen most often on the lakes of Fermilab. Bonaparte's gull is named in honor of Charles Lucien Bonaparte, the eminent French zoologist and nephew of the Emperor Napoleon.

Fallen Nuts

Squirrel scientists have found that gray squirrels are sloppy eaters during late summer and early fall, but not in the winter. During the warmer days, gray squirrels eat hastily and often leave bits of nut behind with the shells. As autumn turns to winter--when the calories from the nutmeat become more important--squirrels become more diligent in their dining habits. They double and occasionally triple the amount of time they spend on each acorn, eating much more carefully and wasting much less. When squirrels find a fallen acorn in the fall, they face a decision: eat it immediately or cache it for later. Some research indicates a squirrel's decision to "eat or cache" is based on various factors, including probability of early germination coupled with the levels of tannin and lipids inside the acorn. If the acorn is likely to germinate soon, it will be eaten soon. The more tannin and lipids in the nut, the more likely it will be stored. Those acorns with low levels of tannin and lipids are consumed on the spot.