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Recent habitat improvements at Hendrickson Marsh will be on display this fall

  • 8/19/2020 6:54:00 AM
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Sitting smack in the middle between Marshalltown and Ames, the 850-acre Hendrickson Marsh Wildlife Area is a get-away-from-the-crowd kind of place, enjoyed by kayakers and bird watchers, and outside of opening weekend of duck season, by hunters.

With a mix of forest, prairie and a 200-acre wetland, Hendrickson Marsh is an important refueling spot for migrating birds each spring and fall. It’s home to diverse a grassland bird population, deer, turkeys, pheasants, doves and ducks. There’s a large tiger salamander population and sandhill cranes have been documented nesting here.

The wetland was dewatered as part of a renovation project to eliminate rough fish that got in to the system and to re-establish the vegetation. Standing in the parking lot on the southside off County Highway E63 on this late July morning, the project is nearing completion.

Wildlife biologist Josh Gansen said he plans to begin holding water in mid-August and given the marsh’s 8,400-acre watershed, he said it can refill in a hurry.

“We want to give the vegetation time to grow and mature. I’m hoping to get a nice response from the Bidens, millet, rice cutgrass, smartweed, river bulrush – good food for migrating waterfowl,” Gansen said. “The thing about a large watershed is that if we get a one-inch rainfall, we’ll fill up quick. I expect it to be great for walk in teal hunting. Early on, it could be a little tough for a boat.”

Work to improve the habitat extends beyond the marsh to the surrounding timber and prairie areas.

The prairie area on the south side between the parking lot and the marsh was treated with prescribed fire this summer to eliminate the encroaching brush. On the northeast corner, Gansen is using goats to help manage the vegetation when prescribed fire is not an option.

“We’ve used goats at other areas successfully, and we were fortunate enough that one of our neighbors has goats she needs to graze. They browse everything up to four feet which allows us to come in with equipment to remove the brush and avoid obstacles normally hidden by the taller vegetation,” he said.

Outside the goat zone, Gansen has been mechanically removing honeysuckle, and invasive shrub, that has been expanding its footprint in a windbreak along the north edge.

So far, Gansen has removed about 25 acres of encroaching and invasive trees as part of the long-term management plan. The brush has been replaced with prairie that will be managed with prescribed fire to reinvigorate the prairie and keep the brush at bay.

Expanding the prairie east and west

A 32-acre crop field on the southeast corner, acquired from the Iowa Natural Heritage Foundation, brought the area out to the gravel road improving access for visitors. Only in its second year, the young prairie is staring to express itself as blazing star and pale purple cone flower are easily visible.

The seed mix came for the DNR’s Prairie Resource Center and was supplemented with additional forbs that were supplied, in part, by a Monarch 3 grant from the National Wild Turkey Federation.

“The prairie has had a good response and provides good room for pheasants to run,” Gansen said.

A similar 30-acre parcel was acquired on the west side extending the area out to the gravel road. It too was planted to prairie.  

“It’s a nice buffer to the marsh,” Gansen said.

Popular dove hunting spot

A 15-acre sunflower field was installed on the north side to accommodate the jump in interest for dove hunting. Pheasant chicks dart in and out of the field edge. The sunflowers are next to a field that has just been hayed and there is already a lot of doves.


There’s a bald eagle nest near the main boat ramp.

Visitors hike back to fish the marsh outlet, catching mainly bullheads and carp.

Hendrickson Marsh was built in 1968 and named for Iowa State University professor George Hendrickson. A plaque marking the dedication at the parking lot on E63 notes Hendrickson is “A pioneer educator in the field of Wildlife Management.”

In 2007, Hendrickson Marsh was one of the first shallow lakes in the state that was renovated using the new approach of water level manipulation to keep the wetland functioning properly. The goal of that renovation was to eliminate rough fish and to create a channel to help with future renovations.

The marsh has a good muskrat population. It’s also home to painted and snapping turtles, bullfrogs, and more.

Hendrickson Marsh draws hunters locally and from Ames, Marshalltown and Des Moines. It’s frequented by college kids. “When I went to Iowa State, it was the first place I came to duck hunt,” Gansen said.