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
Endangered Species Act of 1973 legislation, crafting a document that completely changed the direction of environmental conservation in the United States. Dr. Bertrand is credited with writing the most challenged section of the Act, the "takings" clause – Section 2. The stated purpose of the Endangered Species Act is to protect species and also "the ecosystems upon which they depend." California historian Kevin Starr was more emphatic when he said: "The Endangered Species Act of 1982 is the Magna Carta of the environmental movement." The ESA is administered by two federal agencies, the United States Fish and Wildlife Service (FWS) and the National Marine Fisheries