Darters, or Anhingas, are found across the world, living near warm, shallow waters. The name darter comes from the fact that they impale prey with their long beaks.
There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN.
If you’re interested in birds, here is a post on the Bharatpur Bird Sanctuary, one of the best known bird sanctuaries in India.
For more information on darters, here is a link to Wikipedia’s description
