Hendrickson: A waterfowl magnet
The featured creature for today is a duck. Not just any duck, but a unique species that is easy to identify once a person gathers a few key markers of its plumage and bill shape. For starters, its name is Northern Shoveler and its Latin name is Spatula clypeata. The bill denotes an obvious marker being much wider near its tip and thus the resemblance to a shovel. Second, depending upon lighting, the head feathers can appear black, or blue or green. The eye has a distinctive yellow ring. Body wise male shovelers have a while chest and a brownish chestnut colored flanks to the body. It back feathers are a combination black and white stripes.
Hendrickson Marsh is just one of several Iowa DNR wetland/marsh habitats. This area 821-acre public land and water complex is located in Marshall County’s southwest corner and Story County’s southeast corner. The land in this vicinity owes its shape and basin profile to the most recent geologic glacial event, the advance over 50,000 years ago and subsequent ice retreat (melting) began about 20,000 years ago. In geologic time scales, this equates to the snap of your fingers. And this earth warming time frame called an interglacial is the time frame we humans are living in right now.
Earth wide glacial systems take a long time to gain momentum as winter snows fail to melt during shorter and shorter summers. Snow accumulations became very thick, hundreds of feet thick, so that the pressure alone causes the bottom layers to become like thick taffy, conforming to the land underneath but also being pushed south by thicker ice masses from the north.
Natural cycles of nature have brought us many past glacial events, at least eight of them according to Iowa’s rock history during the last 2.1 million years. Each glacial advance was an unstoppable force. Between each glacial event were interglacial warming periods, shorter in geologic time but still warm compared to the bitter cold and ice of glacial maximums.
Still, it happened during the Wisconsinan time frame. It covered all of Canada and had its leading edges and signature landscape changes brought to bear from Washington State to Maine. In Iowa, one large advancing ice edge element of the Wisconsinan covered all of the Dakotas, Minnesota, most of Wisconsin and a big portion of north central Iowa. It was along the eastern edge of this ice edge, the lateral moraine, that today’s area known as Hendrickson Marsh is found. Most likely a large segment of glacial ice was left standing high and dry, so to speak, while the rest of the glacial melted and withered away as the earth’s climate went into a natural warming trend.
The stranded ice block did melt over the course of several hundred years. As it melted, all kinds of material imbedded in the ice matrix flowed out of the ice with run off water. Glacial ice is full of anything it sweeps up during its thousands of mile journey from the Hudson Bay vicinity. Lots of rocks and loose material resulting from constant grinding action of moving ice accumulated as sands, gravels, pebbles and sticky clay-like soil grains. All of this material was left behind in what we see today as the surrounding hilly landscape on all sides of the water filled basin.
In the mid-1960s, the state of Iowa via the Iowa Conservation Commission purchased the first parcels totaling 601 acres. In 1988, additional lands were added and later on a few smaller segments were acquired to bring the total acreage to 821. The name for this natural wetland was given in honor of Iowa State University professor George Hendrickson. It is managed as a wetland habitat with periodic water level drawdowns and refills. Timing is important to maximize the food value for migrating birds of all kinds, not just waterfowl. Now in our spring time of 2018, waterfowl and the colorful Northern Shoveler are making full use of the marsh to rest, eat and prepare for a continuation of their migratory journey.
When you travel to Hendrickson, do observe the bald eagle nest southwest of the boat ramp parking area. Do use a good quality bird book and optics to identify as many species of wetland birds as you can list. Do whatever it takes in terms of time to critically observe the natural events transpiring before you eyes within this old glacially formed now water filled landscape depression. It is a nice place to visit to help satisfy your desire to enjoy nature. Have a great day.
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This week a planned PRAIRIE GRASS management fire was conducted at the Grimes Farm. Lots of people showed up observe from a safe distance to see how fire advanced through last years six foot tall dry stems of Big Bluestem, Indiangrass, and Switchgrass. Fire invigorates and refreshes native grasses. Access to warming sunlight is brought about by not having last years growth in the way. The growing points of the new grass shoots is just below the soil surface and free from damage to the massive root system lying 6-10 feet underground.
A safe prairie grass management burn starts with several factors. One entails fire breaks, or mowed edges or delineations of what is desired to be burned and what is left for another year. Fire lanes are best created the summer or fall prior to a spring burn. Next comes weather conditions of wind, and humidity levels. Of course fire management training is required of the Marshall County Conservation Board staff. They have been to school to learn those techniques of safe burning.
Equipment items suitable for the task of burning are required. And then add a heavy dose of experience to know how a grass fire can be made to slowly burn into the wind.
After the fire is finished with its work, Mother Nature will gear up its plant population of grasses and forbs (flowers) to grow as new rains and warm sunshine provide the ingredients for a new vigorous growth of the prairie during 2018. Hiking through a recently burned prairie can reveal lots of interesting things. Look critically at the land, and then come back periodically during late spring and summer to see how the prairie transforms itself into a beautiful new vegetative cover to the land. You can learn a lot by observing a refreshed prairie grassland.
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Did you know that 2018 is an Anniversary Year, the 100th in fact, of the Migratory Bird Treaty Act. It was an important piece of federal legislation a century ago to enhance a cooperative plan between Canada, the United States and Mexico for birds moving back and forth each fall and spring. Our human lines on a map that designate boundaries to us is a non-important item for birds. Going from and to wintering areas and back to summer time breeding landscapes is just par for the course. It is what migratory birds must do to live out their life cycles.
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Helpful hint for inquisitive kids: If you want them to grow up to actively care about the environment, allow them to explore and have plenty of play time outdoors. Match this with little games involving critical thinking and good observation. Collect rocks, smell spring flowers, walk a creek to poke around in places where frogs hide and just enjoy the experiences that nature offers. Tag along on mushroom hunts, turkey hunts or a deer hunt in the fall. Do this well before the kids get into their teen age years. The end product will be a kid grown up to appreciate the natural world. That is a nice outcome.
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.