McNary National Wildlife Refuge's rich diversity of wetland habitat was created by the damming of the Columbia River. Although more wetland habitat was formed, the dam highly altered the natural ecosystems and provided management challenges for the U.S. Fish and Wildlife Service. These challenges include artificial river operations, widespread nonnative invasive plant and animal species introduction, and extensive land use conversion and fragmentation. Refuge staff use a variety of carefully chosen habitat management techniques to maintain, recover, or enhance habitat for wildlife.
Management of seasonal wetlands involves the manipulation of water levels to encourage native food supplies and promote the diverse wetland plant growth that provides a variety of food and shelter for wildlife. Some wetlands are burned and disked to remove undesirable plant growth and create open areas. Shoreline burning and mowing also create open beach areas that waterfowl use for courting, feeding, resting and raising young. Seasonally flooded wetlands provide resting and feeding areas and are especially important to waterfowl during fall migration.
Upland areas, replete with sagebrush, rabbitbrush, and bunchgrasses, provide forage for deer and nesting sites for pheasants, ducks, California quail, and burrowing owls. Refuge managers improve uplands through prescribed burning, removal of exotic weed species, and planting of native grasses.
Riparian areas supply food, plants, water, nesting sites, and shelter for a wide variety of wildlife. Cottonwoods and willows in riparian areas provide essential nesting habitat for migratory songbirds like yellow warblers and willow flycatchers. Management practices in riparian areas include planting native willows and cottonwoods.
Approximately 700 acres of refuge lands are irrigated croplands, which provide food and cover for wildlife. Farmers grow corn, wheat, alfalfa and other crops under a cooperative agreement whereby the refuge's share of the crop is left in the field for wildlife. These crops provide an extremely valuable source of high energy food for waterfowl, especially in late winter when other food sources may be exhausted or covered by snow.