During the fall migration season, visitors may see 15 different species of duck and up to 200 different species of birds. Waterfowl and bird watching guides and checklists are available at the visitor contact station and headquarters office. Birds of particular interest are wood ducks and bald eagles.
Wood ducks commonly nest on the refuge. Males are iridescent chestnut and green, with ornate patterns on nearly every feather; the females have a distinguishing profile and white pattern around the eye. The small waterfowl have a distinct call. The female makes a loud "oo-eek, oo-eek" sound when disturbed and taking flight; males have a thin, rising and falling zeeting whistle. Listen for their call while walking through the flooded forests of the Gilbert Lake division.
Some of the largest wintering concentrations of bald eagles in the contiguous 48 states are found along the Mississippi and Illinois rivers. More than 500 of these majestic birds have been counted near the Illinois-Mississippi Rivers confluence as they gather to feed in open water areas. The eagles usually begin to arrive in October and stay until early spring. Several adult eagle pairs remain throughout the year to nest and raise young near the river.