Colo Bogs a remnant of glacial ice 

COLO BOGS has been known for decades as a wetland complex a few miles west of State Center. This area of land is relatively flat to slightly undulating in topography. The reason for the land surface’s shape is due to the geologically recent Wisconsinan glacial system which penetrated this area about 14,000 years ago. This was the last glacial event that still has implications for Iowans who live in the area at the present time. A massive tongue of ice came out of Canada sliding southward over the Dakotas, Minnesota and north central Iowa. Today’s topographic and soil association maps clearly show the “thumb print” of the ice covering as it once existed in Iowa.

Glacial ice worked like a big bulldozer blade to push, gouge and shape the underlying parent material soils. While the land was generally leveled out, there still existed many dips and draws, hummocks and low ridges. The soil mixture left behind was called glacial till, a multitude of organic matter, sands, silts and clays, rocks and pebbles in addition to whatever else the advancing ice gobbled up and froze into its core. When the ice melted, in its slow but somewhat erratic decline, huge volumes of water ran out of the glacier during each summer high-melt time periods. Melt water cut through the ice mantle, gradually exposing imbedded rocks, sands, gravels and other material. These items were sorted by running water into accumulations from small to very large. In time, water accumulations began to collect and form the basis for the creeks, streams and rivers we see today.

In other places under the glacial ice, the settling out of material was more gradual. It is this setting that the Colo Bogs reminds us of today. When one travels west from Marshalltown toward Ames along Highway 30, a slight rise in elevation occurs about two miles west of State Center. This hill top represents the edge line of the old Wisconsinan glacier. Maybe the ice was not too thick here. However, at the Ames area, glaciologists have estimated the ice was at least 800 feet thick. If one could dial in the “way-back machine” and travel north on the surface of the glacier toward the Minnesota state line, the ice would have gotten progressively thicker. Anyway one looks at it, this is a lot of ice water locked up in a vice-like hold.

This is a great example of the natural cycles the earth goes through periodically. While the big tongue of ice covered north central Iowa, the entire glacial system it was a part of stretched from Washington State to Maine. One might want to refer to and review my story of the origins of Canadian glacial ice foci that I wrote about on Feb. 23 in this column. There was not much of Canada that was not covered in thick ice mantles at that time. While those glacial conditions were impressive, do take note that Iowa’s bedrock and soil groups tell of at least eight or nine previous glacial cooldowns that were as much or even more extensive than our most recent tangle with a cold climate. So the takeaway idea to note is this: The earth warms and the earth cools over time periods of hundreds of thousands of years. It does so in response to galactic, gravitational and cosmic forces interacting with undulations of the sun in one itty bitty arm of the solar system we are a part of.

The Cole Bogs Wildlife Area is a history lesson for us to use to improve our understanding of the ebb and flow of natural life on the land surface. The interglacial warm period we live in today is evidence of this point in time whereby we can live, work and enjoy the bounty of the land and what it can provide. Our present mid-continental climate allows us to exploit our situation. If we do so carefully, the land can sustain us via the crops it grows and the livestock it supports. The Colo Bogs area has its own mission, to provide wildlife such as migrating waterfowl, resident mammals and a host of birds (resident and migrants) a place to rest, feed and call home in a landscape originally shaped by glaciers and highly modified by mankind. We can afford to cherish, protect and savor other wetland complexes similar to this. One way you can help in this goal is to purchase federal and state duck stamps. This fall, when the ducks return, go to Old Highway 30 west of State Center. Look at the land. Remember its glacial origins. Marvel at the role this wetland plays in survival of all kinds of wildlife.

STATE FAIR is here. The big brick icon just inside the Grand Avenue Entrance on Des Moines’ east side, the DNR building, is a must-stop for many folks at the fair. Central to its displays are the large aquariums filled with native fish species from all over the state. People love to see the fish because this is a view most never have the chance to witness. Humans fish above the surface in hopes of putting the right lure at the right time below the surface for a quarry that is invisible. The fish at the state fair are very visible.

There will also be a kids’ archery range, park rangers to visit with, conservation officers and other field staff, all experts in their segment of natural resource management. There will be taxidermist rendition of a mountain lion and cougar to see, the one taken within the city of Des Moines last year. In the courtyard will be programs for kids, adults too, and even a snowmobile simulator to test your safety issues. A waterfowl pond will have lots of critters to see up close. Do a bit of other bird watching and get great information about Iowa state parks. The fair runs through Aug. 18.

FISHING REGULATIONS have been relaxed at Green Castle for the balance of this year. Extensive fishery habitat work is being performed while the water within the lake is held at artificial low levels. The low water is part of the strategy to eliminate all the fish. Fishermen and ladies can take as many of the fish they desire using traditional hook and line, nets, trot lines or jug fishing. Names and addresses must be attached to trot lines. Later this fall, DNR fisheries crews will use rotenone to smother any remaining fish. When all shore line work is done, and the old fish population is gone, valve gates in the dam will be closed. Fall rains, winter snows and spring rains will be allowed to refill the impoundment. With new water, new fish structures, such as stake beds, and sand or rock edges, a restocking of fish will be accomplished by the DNR. It will take time for these fish to grow. Growth should be fairly rapid with lots of exposed weed beds for food and cover. Green Castle will remain open all summer, fall and winter for normal park activities. For details and updates, call the Marshall County Conservation Board at 752-5490.

PHEASANT ROADSIDE counts are going on right now in all parts of the state. Some areas will have few roosters to see. Others will have some. It is trend lines the upland game biologists are interested in, to see if any part of the pheasant population is losing, holding its own or gaining strength. What is known is the pheasants do best after mild winters with less than 30 inches of snow. If that is followed by relatively warm and dry spring weather with less than 8 inches of rain, pheasant numbers can respond well. Due to the high volume of spring rain this year, it is already pretty well-assured that game birds were negatively impacted.

For this scribe, a recent walk-about at the Marietta Sand Prairie was good news. My pathway flushed a hen, and, a bit later, a rooster made a big racket as he flew away. There will be some birds holding onto life. For biologists and officers conducting the roadside counts, they will be looking for pheasants, their chicks and noting the size of the broods. This data is important as each of the 30-mile-long standard routes is slowly driven by DNR staffers. Results will take awhile to compile. I’ll let you know the good, bad and the ugly when I know about it. Stay tuned.

Short notice: If you are a Sporting Clay advocate, there is still time to attend tomorrow’s shoot at the Fayette County Conservation Club near Oelwein. Registration opens at 8 a.m. This is a fun shoot as a fundraiser for cancer research. If you have time, make the trip to Oelwein.

Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at PO Box 96, Albion, IA 50005.