The San Luis National Wildlife Refuge in the San Joaquin Valley of central California is one of the great remnants of a historically bountiful wintering grounds for migratory waterfowl on the Pacific Flyway. Located in the Bear Creek, Salt Slough, and San Joaquin River floodplain, it hosts a myriad of tree-lined channels and oxbows, wetlands and native grasslands. Thousands upon thousands of mallard, pintail, green-winged teal, and ring-necked ducks flock into the managed wetlands; while the wood duck lives throughout the tree-lined slough channels.