Historically, the Osage River Bottoms IBA was a complex of bottomland prairie, marsh, and forest (Nigh and Schroeder 2002). Today, the IBA is mostly protected marsh and bottomland forest, with little cropland. Eighty-seven percent of the Osage River Bottoms IBA is publicly-owned conservation land. This includes the following US Army Corps of Engineers (USACE) lands managed by the Missouri Department of Conservation (MDC) as Conservation Areas: Cephas Ford Access (to the Marmaton River; 101 acres, 41 ha), Douglas Branch Conservation Area (CA) (521 acres, 211 ha), Four Rivers CA (13,741 acres, 5,563 ha), and Schell-Osage CA (8,596 acres, 3,480 ha). The IBA also includes The Nature Conservancy's (TNC) Marmaton River Bottoms Wet Prairie (566 acres, 229 ha). USACE manages the remaining public land, comprising 16,643 acres (6738 ha) surrounding Harry S. Truman Lake.

For IBA map, click here.

The Osage River Bottoms IBA presents abundant wetland habitat for migrating and breeding waterbirds. Bald Eagles nest on the IBA—and the surrounding vicinity (Jacobs and Wilson 1997)—in the highest densities in the state. Nesting Mississippi Kites and Red-shouldered Hawks have been found on Four Rivers CA, and Scissor-tailed Flycatcher and Prothonotary Warbler on Schell-Osage CA (Palmer and Palmer 2001). Thousands of waterfowl pass through the IBA each year (over 30,000 individuals were recorded at both Schell Osage and Four Rivers CA during 2005 during MDC’s Midwinter Waterfowl Survey), along with good numbers and diversity of shorebirds.

The Osage River Bottoms IBA is included in MDC’s Marmaton / Wah’ Kon-Tah Conservation Opportunity Area (MDC 2005), where MDC describes conservation challenges on private land of habitat destruction and fragmentation, fire suppression, altered hydrology, invasive plants, and landowner participation in conservation efforts.