Koshi Tappu Wildlife Reserve is one of the finest birding sites in Asia. It was established as a wildlife reserve in 1976 with an aim to protect the last remaining population of Asiatic Wild Buffaloes in Nepal. The reserve has a total area of 175 sq. km. The principal habitats in the reserve include: wetlands, grasslands and small patches of riverine forest.

To date this is the only Ramsar Site (a wetland of international significance) in Nepal. More than half of Nepal's birds are recorded from Koshi Tappu! Among the mammals, besides Wild Water Buffaloes, the elusive Gangetic Dolphin and Fishing Cat are occasionally seen here.

Many small marshlands, pools and grasslands are formed which provide a haven for birds and birdwatchers alike. The vegetation near these banks holds many passerines. In addition, large agricultural fields that lie adjacent to the reserve make fine habitat for many birds. The finest birding sites in and outside the reserves are located between Koshi Camp and down south all the way to the barrage. Within this stretch many birds and mammals are found that offer the experience of a lifetime.