Summer 2001

Here's what's debuting this season on nature's stage in Chicago Wilderness

by Jack MacRae

EARLY SUMMER

Mussel Beach
People who frolic in the shallows of our lakes, ponds, and rivers are probably familiar with clams. Our waters hold a wide variety of these bi-valves, some of which are quite common as they can survive in polluted, silty waters. These include the giant floaters and the charmingly named pigtoes. Others, such as the rare creek heelsplitter, are intolerant of pollution and can be found only in clear waters such as the Kishwaukee River system in McHenry County and portions of the Kankakee.

Premature Withdrawal
Goofy as this may sound, the "fall" bird migration is now taking place. Beginning in late June, certain shore birds are already beginning their long treks south. Local researchers have noted the early arrival of least sandpipers, short-billed dowitchers, and the greater and lesser yellowlegs. They are coming from their summer breeding grounds in arctic Canada, en route to their warm, winter home along the Caribbean shoreline. It seems the first to arrive are the worst deadbeat dads among the adult males. They’re followed a few weeks later by the adult females, and finally the abandoned precocial youngsters.

MIDDLE SUMMER

Must Be Jelly
Very few people — even longtime students of local fauna — are aware of our freshwater jellyfish. Uncommon, craspedacusta are usually found as colonial polyps, attached to the bottom of a lake or pond. But as the water warms during the summer, the medusea, or free swimming stage, may break away from a polyp tip and float through the water. With their tentacles hanging down from their gelatinous, bell-shaped body, freshwater jellies look exactly like the marine species of jellyfish, although ours are usually under 2 cm in diameter.

Embryonic Journey
I don’t like to say that some animals are smart and others are stupid, unless I’m referring specifically to politicians. But if you compare the size of the brain cavity of a raccoon with that of an opossum, you will see that our resident marsupial has a tiny little brain. But no matter, opossums have done just fine, adapting well to our suburban landscape. During the summer, and after an amazingly short gestation period of less than two weeks, the living embryos of the opossum emerge and crawl along mom’s belly to the marsupium, where 13 nipples are located. These peanut-sized babies will lock on to their source of protein, firmly attaching themselves while they continue their development. If there are more than 13 babies, some will be out of luck and will quickly starve.

The Cure
Eddie Cochran may have sung about the summertime blues, but he might have sung a different tune if he watched a male indigo bunting belting out his song in the midday sun. Buntings are members of a group of birds known for their sexual dimorphism, with the males often exhibiting brilliant colors in contrast to the earthtone-colored females. Other local members of this fetching subfamily of finches include cardinals and grosbeaks.

Desert Life
For those of you who like both kinds of music — that is, country and western — our native cacti are now in bloom with their large yellow flowers. Prickly pear are the only North American member of the cactus family found east of the Mississippi River.

In the Chicago Wilderness, prickly pear often grow on sandy ridges among stands of black oaks. Early naturalists reported them being especially abundant along the Lake Michigan shoreline, south of the burgeoning metropolis of Chicago. These days, our cacti can be found in the Braidwood Dunes, the Indiana Dunes, and Illinois Beach State Park, near the mouth of the Dead River.

END OF SUMMER

Just Ducky
Years ago, I worked with a girl whom our boss called "Ducky." I originally thought it was because she waddled a bit when she walked. (Boy, I hope she doesn’t read this!) But I later learned it was because her last name was phonetically similar to "teal," the blue-winged and green-winged variety of puddle ducks we have in our quiet ponds and lakes.

Blue-winged teal and green-winged teal are small, fast flying ducks that will be one of the first to leave our area for more tropical climates. They might even leave before my kids start school in the fall. Perhaps some of our local teal will be among the huge congregation of waterfowl that will spend the winter in Brazos Bend State Park, in southeast Texas, close to where my former co-worker now resides with her husband and kids.

Snake Thespians
During the last two weeks of August, the eggs of the hognose snakes will be hatching after an incubation of 40 to 50 days. Using an egg tooth to slit the leathery shell, the young snakes will begin searching for toads, their favorite meal.

The defensive antics of a hognose snake are well known among reptile enthusiasts. When feeling threatened, the snake ominously inflates its neck — like a cobra — and hisses loudly. It will strike with quick, short jabs. In reality, though, these actions are mostly bluster as hognose snakes rarely open their mouths when defending themselves. If the perceived threat continues, hognose snakes will play possum, feigning death by lying on their backs, even going to the point of dramatically oozing drops of blood from their gaping mouths. Their acting ability would make DeNiro proud.