KoshiTappu Wildlife Reserve lies on the flood plain of the Sapta-Koshi in Saptri and Sunsari Districts of eastern Nepal. The area is defined by the eastern and western embankments of the river.KoshiTappu Reserve, gazetted in 1976, was established mainly to preserve habitat for the remaining population of wild buffalo in Nepal. KoshiTappu is a rectangular shaped reserve, approximately 10 km wide and 10 km long, stretching northward from the Nepal/India border along the SaptaKoshi River. The SaptaKoshi is one of the three main tributaries of the Ganges. The reserve offers important habitat for a variety of wildlife. The last surviving population (about 100 individuals) of wild buffalo or arna are found here. They are distinguished from domestic animals by their much bigger horns. Other mammals occurring here are hog deer, wild boar, spotted deer and blue bull. The reserve also assists the local economy by providing fishing permits and allowing the collection of edible fruits and ferns in season. A total of 280 different species of birds have been recorded in the reserve. These include twenty species of ducks, two species of ibises, many storks, egrets, herons and the endangered swamp partridge and Bengal florican. The Koshi Barrage is extremely important as a resting place for migratory birds and many species recorded there are not seen elsewhere in Nepal. The endangered Gharial crocodile and Gangetic dolphin have been recorded in the Koshi river.