Winter 2001

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

by Jack MacRae

THE BEGINNING OF WINTER

Our Native Pines
Late December seems an appropriate time to write about pines, as assorted cedars, firs, and spruce are being hawked as Christmas trees. But Chicago Wilderness has only two native species of pine–the white pine and the brilliantly named jack pine. Both have been growing here for thousands of years while all the others have been introduced from other regions. Up until the time of settlement in the 19th century, white and jack pines were abundant in the sandy soils adjacent to Lake Michigan. The great majority of them were harvested for lumber to build the early buildings in Chicago. At the Indiana Dunes National Lakeshore, the shifting sands have covered and uncovered stumps of white pines that are older than the Great Pyramids in Egypt.

Rough Legs
A few rough-legged hawks have begun their annual winter sojourn, down from their summer nesting grounds around Hudson Bay. Prairie in the winter, their habitat is tundra in the summer. These misnamed buteos actually have soft legs, with a layer of feathers covering their tarsi. Approximately every four years or so, there is an increase in the number of northern birds of prey including rough-leggeds and snowy owls. This irruption is caused by the cyclical fluctuations in the rodent populations, creating a situation where there are a lot of predators and relatively few prey. When this happens, winged hunters are forced to expand their winter range to the south.

THE MIDDLE OF WINTER

Poop as Communication
The crushed limestone trails that wind through our forest preserves seem to serve two purposes. First, they enable people to walk through the preserve, ideally seeing nice things without causing damage to the plants and animals. The other purpose of our trails is to provide a place for coyotes to go to the bathroom. Using their feces as a means of communication, coyotes are careful to place it in a location assured of being well traveled.

At a glance, coyote scat looks a lot like dog poop. But if you get down on your hands and knees and look real carefully, you’ll notice coyote poop has lots of hair. Domestic dogs usually don’t get a lot of hair in their diet. (I was kidding about getting on your hands and knees. Most people are able to see the hair while standing, without drawing too much attention to themselves.)

Sycamore: A Tree with Balls
There will be a full moon on February 8, 2001. If there is a fresh layer of snow, it would be an ideal night to sneak out and pay a visit to our stately sycamore trees. Their smooth, gleaming upper branches contrast beautifully against the dark night sky. Dangling from the top branches are their balls, distinctive spherical seed clusters that will break apart during the gusty winds of spring.

Sycamore trees are common throughout the valleys of the lower Des Plaines and Kankakee River systems. They are uncommon in the northern section of Chicago Wilderness.

Gulls of Winter
Most of the sleek gulls that all year long patrol the skies above our landfills and strip mall parking lots are either ring billed or herring gulls. But at this time of year, large majestic gulls known as black-backs are soaring over the cold waters of Lake Michigan. With distinctive slate black feathers on their wings and across their shoulders, these dashing birds may finish the winter in our area, then take off and spend the rest of the year cruising the waters off the coast of northeast Canada.

Most of the visiting black-backs are youngsters, their plumage containing streaks of gray and pale brown. They don’t receive their striking adult plumage until they are four or five years old.

Greater black-backed gulls are a little bit bigger than lesser black-backed gulls. Say that three times fast.

THE END OF WINTER

Thawing Frogs
This time of year some wood frogs are frozen as a fish stick. But no need to worry. They’ll soon be defrosting and hopping down to a local flatwoods pond, eager to procreate their species. Wood frogs have the shortest window for breeding activity of our local frogs. As the air and water temperatures rise to 41 degrees, wood frogs show slight breeding activity. When the air temperature rises to 50 degrees and water temperature reaches the upper 40s, breeding activity reaches maximum intensity. In a few short weeks it will be over and these dark frogs with the black mask will quickly return to their solitary lives in our mature, mesic forests. Wood frogs are uncommon in northeastern Illinois, but frequent in northern Indiana, and common farther east.

Looks Like Liver
A very early blooming woodland wildflower — hepatica — is often found on slopes in our wet forests. The fragile flower emerges from the decaying red oak leaves. The spring leaves of the hepatica are actually from the previous growing season, still green after several months under the snow. The green color, of course, is leftover chlorophyll from last year’s photosynthesizing.

Hepatica gets it name from looking like liver. The two species of hepatica in our area are the sharp-lobed and round-lobed, referring to the shape of that livery leaf. The round-lobed species prefers to grow in soil slightly more acidic than the sharp-lobed variety.