- The refuge is important for waterfowl and waterbird production, secure cover for molting waterfowl, and a waterfowl migration staging area. Waterfowl staging on the mashes in the fall provide hunting in an area over 20 miles in all directions from the refuge.
More than 250 bird species have been recorded on the refuge with over 125 species using the area for nesting, including many neotropical species and other species of concern. The refuge is also of international importance from the standpoint of water management on an international river.
Five dikes and water control structures create over 23,000 acres of managed freshwater marsh. Other habitats are native and tame grasslands, sandhills with a mixture of prairie and oak and aspen woodlands, a riverine system, riparian woodlands, floodplain meadows, and many small wetlands and old river oxbows.