CONESVILLE, Iowa - Cone Marsh is the most diverse wetland in Southeast Iowa. It’s part of the first in the nation Amphibian and Reptile Conservation Area and has a history of waterfowl hunting that dates back to the late 19th Century.
A recent project to replace a failing water control structure has allowed area managers to manipulate the water level in the wetland to encourage vegetation that provides food and cover for waterfowl and other wetland birds.
In short – for wetland wildlife, Cone Marsh Wildlife Area is kind of a big deal.
“It’s the most diverse wetland complex in southeast Iowa,” said Andy Robbins, wildlife biologist with the Iowa Department of Natural Resources. “If you’re in pursuit of wetland birds, whether with gun or camera, they’ll likely be here.”
Cone Marsh’s 728 acres benefits from its location adjoining privately owned marshes on its east and south side, bringing the combined habitat to more than 1,800 acres, of which, 1,000 acres are wetlands. The neighboring marshes benefit from a recent project at Cone Marsh allowing wildlife experts to better control the water level in the wetland to produce vegetation and food needed by ducks during the migration.
Fixing the infrastructure
The previous water outlet structure was too small to manage the water level in the marsh and was in a failing state, threatening the integrity of the dike. The structure was replaced in 2017 that allows Robbins to manipulate the water level and the habitat has had the desired effect making Cone Marsh more attractive to waterfowl, and to migrating wetland and shorebirds.
Robbins has been able to manage the water level to produce different outcomes, like the late drawdown this year that produced a good crop of millet, barnyard grass, pickerelweed and smartweed on the north end.
“This new structure was part of a North American Wetland Conservation Act grant and was engineered by our partners with Ducks Unlimited. It is a good design and it should last for decades,” Robbins said.
Hunting History
Cone Marsh and its surrounding wetlands have a history of waterfowl hunting dating back to the late 19th Century. It was an area used by hunters who would harvest ducks in large numbers then taken to the nearby train station and sent to markets across the country. The practice of market hunting was banned as part of the Migratory Bird Act of 1909.
Private hunt clubs adjoining the marsh have been around since the early 1900s. The public area was assembled in the 1960s and 70s, with the first acquisition coming from the Iowa City Moose Lodge that owned one of these hunt clubs.
The area draws hunters from Muscatine, Johnson, Washington and Louisa counties. It’s a popular place during the regular duck season and to avoid the crowds, Robbins advises to come on a week day. “Acre for acre, more people hunt here than at any of my areas,” Robbins said.
Restoring the Prairie
On the surrounding upland, Robbins and his staff have been focused on eliminating the thick, dense groves of black locust and honey locust and creating a diverse native prairie plants like blazing star, rattlesnake master, wild bergamot, coneflowers, big and little bluestem and more. A few small hayfields are part of the management plan to provide places for pheasants to nest.
“It’s a constant battle to keep the unwanted trees from creeping back on the prairie and marshland, but we’re getting a handle on it,” he said. “It’s been a lot of work and it’s nice to see that work is getting a response from wildlife. We’ve always had wetland birds here, but now grassland birds like bobolinks, are showing up.”
Birdwatching
Cone Marsh draws birdwatchers year-round from Iowa City, Washington and Muscatine, but visit less often during the hunting season. They tend to set up spotting scopes more frequently at the north end of the wetland.
Sandhill cranes have been nesting here since the 1990s. Black necked stilts, avocets, ibises, a large variety of shorebirds, trumpeter and tundra swans all migrate through Cone Marsh. In the spring, tens of thousands of snow geese pass through, which is a more recent development,
Cone Marsh has been a trumpeter swan release site but for whatever reason, they haven’t nested here. “I don’t know why,” he said. “Trumpeters like everything that’s here. I just don’t think that they like to nest this far south.”
Reptiles and Amphibians
Cone Marsh is included in the Amphibian and Reptile Conservation Area, which covers parts of seven counties in Southeast Iowa where there’s the highest number of amphibian and reptile species, including a high percentage of Iowa’s rarest amphibians and reptiles. An important emphasis of this area is to support healthy source populations of amphibians and reptiles, but is especially focused on Iowa’s declining amphibians and reptiles.
“Blanding’s turtles are here, tons of other herps are here including frogs, turtles, and all the usual water and upland snakes,” he said.
It’s also a place popular with those who enjoy catching bullfrogs.