Kirwin National Wildlife Refuge in Kansas was established in 1954 to conserve and manage wildlife, especially migratory birds. Along the North Fork of the Solomon River, the Kirwin Dam and reservoir help create wetlands within a transition zone where tallgrass and shortgrass prairie meet, producing notable biological diversity. More than 300 species of birds, mammals, reptiles, amphibians, and fish have been recorded there. In favorable conditions, up to a million ducks and geese gather there, while other important bird species migrate through or nest in the refuge. It remains both a major conservation area and a place for public recreation and education.