Rock River Hill Country

This week's Natural Division is the Rock River Hill Country, just to the East of the Wisconsin Driftless Division encompassing Stephenson County, most of Carroll and Ogle Counties, and parts of Winnebago, Lee, Whiteside and JoDaviess Counties.

This region of rolling, glaciated topography is drained by the Rock River. The soils of this division are thin and are either loess (wind-blown sediment) or glacial till. Two sections make up the division. The Freeport Section is underlain with dolomite and limestone. Outcrops and “dells” occur along streams. The Oregon Section (south central Ogle County) is underlain with sandstone that has formed bluffs, ridges, and ravines.

Prairie once occupied the larger expanses of upland while forests were equally abundant along watercourses. White pine, Canada yew, and yellow birch—northern forest relicts—can still be found in this division. Prairie knobs (islands of prairie that were either too hilly or too troublesome to farm) support downy yellow painted cup and profusions of pale purple coneflower. Castle Rock State Park and Nachusa Grasslands are representative sites of this division.

Right now is a good time to look for pasque flowers as they are one of the early bloomers.

Reptiles Emerging

By Michael Dreslik

As the winter weather fades away and temperatures begin to rise during spring, reptiles awaken from their winter slumber. For many that spend the cold winter underground, it will take many days of sun to warm their blood. Being cold blooded, a reptile’s physiology depends on heat, the warmer they are the faster they can escape predators, catch a meal, and even digest. The first few days of warm weather, reptiles will be somewhat reluctant to venture from their safe haven and may only peer from the shelter of their winter retreat.

During the cool, early spring weather, reptiles are sluggish and vulnerable to a myriad of predators looking for an easy meal so it is important to have a retreat safely at claw. When they do decide to crawl or slither out, they remain nearby their winter retreat and shuttle above and below ground with the rise and fall of the temperature or dive for their retreat if danger lurks. Some species, such as garter snakes, will emerge quickly and begin mating en masse whereas others such as turtles will take longer awaken. Slowly, they will creep out of their winter torpor and begin to bask in the sun’s warmth. As overnight temperatures eventually warm near the middle to end of spring, reptiles will finally venture away from their winter retreat and begin a sojourn for the necessities of life, foraging, growing, and reproducing, returning to their burrows only with the cool fall weather.

Massasauga hiding in the grass

Frog and Toad Calls

by Susan Post

The first faint calls of frogs and toads are often heard during warm spells in late February or early March, but for many species, the warming days of spring bring on their true vocal talents. As both the soil and water gradually warm in spring, frogs and toads awaken from hibernation and assemble in or near shallow water where, as amphibians, they must lay their eggs. In most instances, sounds are produced only by the males, and are usually courtship calls to attract females into a breeding area, but can also be territorial calls to warn other males of rights to a particular spot. Each species has its own distinctive call and breeding period.

Wood frogs are likely to be the first call heard as they are known to herald the retreat of winter. They sound like a soft, ducklike cackling in shallow ponds. The bird-like, whistling peep of the aptly-named spring peeper almost magically appears after the first warm rains of spring. Next to join in the music is the chorus frog, sounding much like a finger drawn across the teeth of a comb. Then come the omnipresent trills of the toads, and somewhat later, the cricket frog will add to the chorus, with mechanical clicks reminiscent of two pebbles striking together. The impressive, double, deep bass notes sung by extremely territorial bullfrogs from May to July have been likened to dueling tubas!

Calm, undisturbed waters with abundant insect life such as swampy, marshy areas, temporary ponds, small lakes, and quiet streams, are all good places to listen to and look for some of these more common toads and frogs. But, toads and frogs are very alert and will often stop calling and leap to the safety of deeper water if disturbed. Also, many species are experts at "throwing" their voices, which makes finding them even more difficult. Simply sitting quietly near one of these likely spots will most often result in actually locating a calling frog or toad. Better yet, for those fortunate enough to live near an active breeding site, the back porch may offer the best seat in the house for these nightly amphibian arias. Although it's unlikely they'll ever threaten the reputation of the Chicago Symphony, the repertoires of toads and frogs create a curious, somewhat captivating, night symphony all their own.

Wood frogs form a frenzied mating ball

Spring peeper

Video 1: Calls of Wood Frogs and Peepers; Video 2: Calls of Illinois Chorus Frogs

Trillium Tapestry

By Susan Post

It is almost April and finally Spring. Winter's gray-brown, threadbare blanket of leaves on the forest floor is rapidly being replaced by an explosion of color. Each day brings a new flower species—bloodroot, spring beauty, trout lily, and Dutchman's breeches—unfurling their leaves toward the sun in the race for sunlight before the trees leaf out. Perhaps the most elegant bloomers of the Illinois' woods are the trilliums Illinois has 9 species of trilliums which are easily recognized as their flower parts are arranged in groups of threes—3 petals, 3 sepals and 3 leaves. When the trilliums are in full bloom it is an indisputable sign that winter is over and spring has arrived!

The first to bloom is the snow trillium, poking through a protective blanket of leaves in mid-March. Sometimes they must push through a layer of heavy, wet snow to reach the warming rays of sunshine. Only 4 inches high and pure white in color, they grow in isolated communities in hilly woods and along limestone cliffs.

Prairie trillium is the most common woodland trillium, occurring in every county in the state. Its green leaves are strongly mottled with brown; the red flower is sessile. In the late afternoon sun the three blood-red petals resemble a candle, lighting the patches of darkening shadows.

For those lucky enough to find a rich, undisturbed woods, they are rewarded with the gleam of the large white blossoms of the Great White Trillium—the largest of Illinois’ trilliums. The waxy white flowers change color as they grow older, going from snowy white, through pink, to deep purple-pink before the petals wither.

Allerton and Lodge parks in Piatt County, Mississippi Palisades State Park in Carroll County, and Edward L Ryerson Nature Preserve in Lake County are good sites to view the trillium tapestry each spring.

The Wisconsin Driftless

The first Illinois Natural Division that we will showcase is the Wisconsin Driftless. This area is found in the NW corner of the state, covering most of JoDaviess County and part of Carroll County.

This area of Illinois lacks the granite boulders present in much of the Midwest and has deep ravines and valleys. From this evidence we know it escaped the glaciers of the Pleistocene. The Driftless Division (drift is glacially deposited debris) is characterized by rugged terrain. The area has not only the state’s coldest winters but also its highest point—Charles Mound. The soils are composed of wind-blown loess, disintegrated rock, and flood deposits. At one time most of the landscape was hardwood forest. Although the glaciers missed this area, debris from their melt waters blocked the southeast outlet of the Apple River, causing it to cut a new channel. As the river cut through the masses of limestone, dolomite, and shale to form its new channel, it also formed a rugged and picturesque canyon. This iceless region provided a haven that allowed certain plants and animals to survive the glacial periods. Bird’s-eye primrose is one of these relicts. One hundred years ago bird’s eye primrose tinted the rocks in Apple River Canyon purple with its blooms. Today isolated pockets may still be found.

Interested in exploring this area? Apple River Canyon State Park and Mississippi Palisades State Park are located in this area.

Skunk Cabbage

by Susan Post

Skunk cabbage, found in the northern 2/3's of the state in open swamps, marshes, and wet woodlands, is Illinois earliest flowering plant. Before the woods awake in spring it begins to bloom in late February or early March. Sheltered and hidden by a few decaying leaves, it bravely pokes through the moist earth to face howling winds, freezing temperatures, and sometimes even snow.

The first part of the plant to appear is not the leaves, but a fleshy protective hood, called a spathe. The hood, emerging dark and ruddy from the mud, is brownish-purple with yellow and green streaks and spots. Although the hood may be 3 to 6 inches tall, its color blends with the surrounding decaying leaves on the forest floor. Using energy stored for months in starchy, tuberous roots, the plant generates enough heat not only to melt through leftover snow, but to maintain summer-like temperatures inside the hood on subfreezing mornings. This is important as each hood incubates a knob-like structure, called a spadix, which is covered with tiny, cold-sensitive blossoms. The insulating walls and curved design of the hood allow eddies of warmed air to circulate around the developing flowers.

All parts of the plant, when bruised or crushed, give off an offensive odor that has been described as a cross between garlic, onions, and decaying flesh. The heat produced by the plant as it grows helps to volatilize the odor, which in turn, attracts carrion flies that are necessary for cross pollination.

A few days after the hood emerges, the leaves pierce the mud. Still unsure of the weather, they remain rolled into compact cones and cower behind the protective hood. As spring advances the odor subsides, the flowers shrivel, and the leaves begin to grow and spread. By summer the skunk cabbage is no longer the ground hugging spathe, but knee-high clumps of caladium-like leaves.

Winter Stoneflies

By Susan Post

The life of fall and winter stoneflies is an exception to the rule that insect activity ceases with the approach of cold weather. Twenty species of the state's 65 native stoneflies emerge during November through March. With a habit of congregating in places exposed to the warming sun's rays, you can see them crawling about on exposed tree trunks, fence posts, or on rocks located close to a stream. The white concrete bridges characteristic of Illinois' highways are a beacon of warmth to a stonefly.

Stoneflies belong to the insect order Plecoptera. In appearance stoneflies are about a half an inch in size, have two pair of wings, and are rather drab in color. The adults, although terrestrial, are seldom found away from water. They are poor fliers with crawling the preferred mode of transportation. The eggs and nymphs are aquatic. The nymphs are often found under stones in streams, hence the common name —stonefly. The nymphs of the winter stoneflies are chiefly plant feeders. The adults feed on blue-green algae or not at all. The nymphs emerge from the water, find a suitable perch and metamorphose into an adult. The adults mate, lay eggs and die, usually living less than a month. The whole life cycle is complete in a year.

Although sunbathing in Illinois from November through March generally lacks appeal to most humans, the bridges over creeks emptying into the Middle Fork of the Vermillion River, or the clear, rocky streams of Southern Illinois are perfect places to absorb the fleeting sunlight of winter and to see Illinois winter stoneflies.

January 24, 2010

White concrete bridges

Beacons of warmth

Nude sunbathers gather

Looking for love

Absorbing weak sunlight

Coupled in pleasure

Winter stoneflies above Stoney Creek

On 8 March, 2010, winter stoneflies were observed on the bridge over the Middle Fork of the Vermilion River at Kickapoo State Park.