The Zapata Swamp is a mosaic of mangrove swamps and freshwater and saltwater marshes that form the largest and best-preserved wetland in the Caribbean. The swamp was designated a Biosphere Reserve in 1999 and forms a vital preserve for Cuban wildlife, a spawning area for commercially valuable fish, and a crucial wintering territory for millions of migratory birds from North America. More than 900 plant species have been recognized in the swamp, and all but three of the 25 bird species endemic to Cuba breed there. All together, about 170 bird species have been identified in the swamp, including the common black-hawk, the greater flamingo, and the world’s smallest bird, the bee hummingbird. It also contains the remaining few thousand Cuban crocodiles. Mammalian residents include the Cuban hutia, a gopher-like rodent, and the West Indian manatee. The manjuari, or Cuban gar, is an unusual fish found only in the swamp. Adjacent to the swamp is the Bay of Pigs, where millions of land crabs breed each spring.