The primary purpose of the refuge is to provide nesting, resting, and feeding areas for waterfowl, primarily ducks.

Since establishment of the refuge, the primary emphasis on waterfowl species has been expanded to include the Eastern Prairie Population of Canada geese.

Canada geese were first observed using the refuge in the early 1940s, and numbers increased gradually to peak populations over 200,000 birds annually.

Although these populations have steadily declined, Swan Lake is still considered a primary wintering area for Canada geese.

This article incorporates public domain material from websites or documents of the United States Fish and Wildlife Service.