Wildlife & Habitat

Canada Geese

At over 33,000 acres in size, Horicon Marsh is one of the largest freshwater marshes in the United States. Recognized as a Wetland of International Importance, as both Globally and State Important Bird Areas and a unit of the Ice Age Scientific Reserve, the marsh provides critical habitat for over 300 species of birds as well as muskrats, red foxes, turtles, frogs, bats, dragonflies, fish and much more. Fall migration on the refuge offers impressive numbers of Canada geese, ducks and sandhill cranes.

  • Muskrat


    Muskrats are often seen swimming or feeding on cattails and make their homes in cattail “huts” throughout the refuge. The original “marsh managers”, they create open areas of water for waterfowl to swim and feed.

  • Redhead duck

    Redhead duck

    Originally established for this species, the refuge supports the largest nesting population of redhead ducks east of the Mississippi River. Thousands use the marsh each year.

  • American white pelican

    American white pelican

    American white pelicans nest abundantly on islands in the interior of the marsh and may be seen feeding in large groups – “herding” fish into shallower water for easier dining.

  • Marsh


    The refuge includes more than 15,000 acres of marsh habitat including dense stands of cattail, bulrushes, burreed, sedges and smartweeds – all great food for ducks, and other migrating birds! European carp and purple loosestrife are threats to marsh habitat. Carp uproot native plants and stir up sediment - impairing water quality - and plants like loosestrife outcompete native plants and decrease diversity of the habitat.

  • Prairie


    Prairie, or grassland, habitat on the refuge helps to stabilize soil, conserve water, and provide nesting habitat for many ducks and other bird species. Plant species commonly seen include big bluestem, Indian grass, cup plant, prairie dock, rosin weed, rattlesnake master and several types of coneflowers. Invasive species to watch for include wild parsnip, which can be dangerous to touch, and Dame’s rocket.

  • Forest


    Small pockets of forest habitat on the refuge provide food and shelter for migrating warblers, resident woodpeckers and other woodland species. They are also the best places during spring to see woodland wildflowers like white trillium, Dutchman’s breeches, rue anemone, trout lily, mayapples and wild geraniums. Several species of oak trees, ash and cherry are found along the trails. European buckthorn and garlic mustard are two invasives often found in forests.