Bayou Sauvage National Wildlife Refuge is the largest national wildlife refuge located wholly within the boundary of the city. The refuge is one of the last remaining marsh areas near Lakes Pontchartrain and Borgne. And despite being within the confines of the city of New Orleans, the refuge, consisting of about 24,000 acres, has a vast diversity of habitat and wildlife. Bottomland hardwoods, freshwater and brackish marshes, lagoons, canals, borrow pits, and natural bayous are all habitats that can be found within the refuge. However, being within the city of New Orleans, places the refuge inside hurricane protection levees that are built to protect the city from storm surges and this has disrupted the natural water flow of the refuge. To remedy this problem, networks of pumps and flap gates were installed to regulate the seasonal water levels on the refuge. And to further aid in maintaining a health water flow; each year the city of New Orleans airlifts recycled Christmas trees into the refuge to act as wave breakers in open ponds on the refuge. This project helps support the growth of native marsh grasses and has helped to re-establish 175 acres of marsh land.
The fact that the refuge is in the middle of a city has done little to deter the wildlife that makes the refuge their home. White-tailed deer, Great Blue Herons, and American alligators are common yearlong residents to the refuge and every winter, thousands of migrating waterfowl stop at Bayou Sauvage. Shorebirds are another group of yearlong residents and the refuge rookery supports over 5,000 nesting pairs. During the fall and spring, many migrant neo-tropic birds make a stop to the refuge as well, and during the summer the mottled ducks commonly nest in the refuge.