Big Branch Marsh National Wildlife Refuge, located on the north shore of Lake Ponchartrain, has over 18,000 acres of marsh, offshore grass beds, hardwood hammocks, and pine flatwood forest. The marshes provide habitat for shorebirds and waterfowl, are critical spawning and nursery habitat for a number of fresh and saltwater species of fish, and are a buffer for storm surge for local communities. Upland habitat on the refuge provides a stopping place for neotropical songbird migrants and habitat for the threatened Red-cockaded Woodpecker.