The presence or absence of water, water depth, and timing are all coordinated to eliminate carp and produce various stages of marsh plant succession upon which these birds rely. Various impoundments, which have been subdivided from the main pool of the marsh using a system of dikes and water control structures, are managed on seasonal, annual, and multiple-year cycles. Because of changing water levels, you may notice some wetland areas of open, deep water, and still others with bare mud. Special care is taken to protect endangered and threatened species that use the Refuge. For example, nesting platforms are provided and monitored for Forster's terns.
Essential habitat is provided for trumpeter swans, great egrets, peregrine falcons, and bald eagles.
You can help by reporting interesting wildlife sightings at the Visitor Center. Also, learn how to properly identify endangered species, especially trumpeter swans, so they are not accidentally shot while hunting.