by Director of Land Preservation and Natural Resources Ed Collins 4/9/15
The swell and swale of the Nippersink Valley in Glacial Park is visible in exquisite detail for the first time in many decades today. Swell and swale is one of those archetypical Midwest terms that saw its birth in the tall grass prairie states and describes a uniquely mid continental landscape phenomenon.
Northeastern Illinois was heavily glaciated and as geologic time measures spans ended just a few minutes ago. The weight of the ice and its steady southward expansion ground away the existing surface features, erasing them as one might remove pencil marks from a sheet of paper. As the glaciers retreated they left a newly sculpted set of land forms that included numerous kettles or depressions and hills including drumlins, kames and moraines.
A geologist friend of mine described the process as similar to decorating a cake with a frosting knife. The cake winds up with high and lows spots where the frosting spread unevenly across that delicious chocolate under layer.
To the newly arriving pioneers in the prairie regions of northeastern Illinois the landscape appeared like an ocean of grass. Each time the winds rolled across that ocean the low parts and high parts or swells and swales, rolled like great waves across a vast inland sea.
In the Nippersink Valley the swells and swales, newly cleared of brush and invasive species and now freshly burned from a March prescribed fire are outlined at the edges. That outline is painted by freshly fallen rain from the first thunderstorm of the season. Last night warm spring rain poured from the skies in a steady deluge filling the swales and outlining them as perfectly as if an artist had painstakingly traced the edges of each depressional area no matter how small.
The swells have their own majesty, each one a high point within an array of interlaced wetlands. From a vantage point of even a foot or two the land appears sinuous and alive with the movement of water in the slightest breeze. Here and there a sandhill crane will stand atop such a swell and survey the extent of the realm laid claim to for the period of time it takes an egg to hatch and a colt to grow to walking size.
In the swales, from the outer edges inward, lie the kingdoms of the dough birds. Dough bird sis a generic term for the sandpipers, snipe, woodcocks and other “peeps” that are critically dependent on areas of low vegetation and exposed mud flats for invertebrate hunting. They wade, chest deep in the shallows, long beaks under the waterline searching the soft mud for food, constantly in motion, fattening up for the push north to the breeding grounds in the tundra.
The name dough bird is also of Midwestern origin, born in the era of the market hunters of the late 1800’s when plover on toast graced the Victorian plate. The prairies had just been settled and the same culture that ate plover would also be the last generation to see flights of shorebirds and ducks blacken the sky.
They hunted them with punt guns, small cannons that propelled enough buckshot to kill dozens of the fat little “dough birds” birds at a time. This same generation would also watch those flocks disappear a couple of decades later as though some great force had simply plucked them from the skies and spirited them away.
Farm drainage, stream ditching and the plowing of the great prairies of the Midwest and Canada doomed the massive flights and drove at least one species of dough bird, the Eskimo Curlew, to extinction.
But today on the hundreds of acres of newly filled swales, open to rain and sky and wind for the first time in decades, the shore birds are anything but extinct. Flocks of 100 and 200 snipe crisscross the potholes as I walk, sometimes settling down in the next flooded swale and sometimes flying across the newly graded stream to alight on the gently sloping banks to walk the shallows of the Nippersink.
Greater and Lesser yellow legs mix with solitary sandpipers and killdeer in other spots and here and there a woodcock whirls off in flight as I step too close.
The stream too seems to be a willing ballet partner today swirling rain laden currents up against the long stilt like legs of the birds as if to say…remember when we used to dance all the way north to the tundra nesting grounds?
If I were a Victorian I am sure I would have preferred my plover not served gracefully on toast, but rather gracefully searching a muddy swale on a bright spring day.