Nalbana Island is the core area of the Ramsar designated wetlands of Chilika Lake. Nalbana means "a weed-covered island" In the Odia language. It is a major island in the center of the lake and has an area of . The island gets completely submerged during the monsoon season. As the monsoon recedes in the winter, lake levels decrease and the island is gradually exposed, birds flock to the island in large numbers to feed on its extensive mudflats. Nalbana was notified in 1987 and declared a bird sanctuary in 1973 under the Wildlife Protection Act.