Ganges Delta trees are found in these areas. The delta region has mangrove trees. It is estimated that 30,000 chital ("Axis axis") are in the Sundarbans part of the delta. Birds found in the delta include kingfishers, eagles, woodpeckers, the shalik ("Acridotheres tristis"), the swamp francolin ("Francolinus gularis"), and the doel ("Copsychus saularis"). Two species of dolphin can be found in the delta: the Irrawaddy dolphin ("Orcaella brevirostris") and the Ganges river dolphin ("Platanista gangetica gangetica"). The Irrawaddy dolphin is an oceanic dolphin which enters the delta from the Bay of Bengal. The Ganges river dolphin is a true river dolphin, but
St. Pierre Island of "Casuarina equisetifolia" trees up 12 m (40 ft) high on its northwestern part, covering a third of the land area. The trees were originally planted as windbreak for the mining camp, and have unexpectedly thrived and spread. Most of the plant species once found on St Pierre are now gone, including the "Pisonia", Suicide Tree ("Cerbera odollam") and rosemallow ("Hibiscus tiliaceus"). Some "Pemphis acidula" might persist. By about 1960, it was noted that the most common herbaceous plant was "Stachytarpheta indica", while the introduced Indian Blanketflower ("Gaillardia pulchella") had established itself widely. Sisal ("Agave sisalana"), Chinese tiolet ("Asystasia gangetica"),