Vankalai wildlife sanctuary, partly a wetland comprises the strips of land on either side of the causeway connecting the island of Mannar to the mainland, Pallimunai, Puliyantivu island, Tiruketiswaram, and Vankalai. It was the fourth Ramsar wetland in the country.

There are about 150 resident bird species and more than 1000 migratory bird species have been recorded in the sanctuary.

Most common birds are Indian spot-billed duck, Eurasian wigeon, Avocet, Common teal, Northern shoveller, Pintail, Gargany, Greater flamingo, Crab plover, Oystercatcher, Red knot, Great knot, Ruff, Lesser crested tern, Caspian tern, Little tern, Heuglin’s gull, and many more.