Koshi Tappu Wildlife Reserve was established in 1976 AD, primarily to protect the grassland, Tappu (small island formed by the Saptakoshi River) and the last habitant of wild buffaloes (called Arnas), spreading in the area of 175 square kilometers and situated in floodplain of the Saptikoshi river (the largest river in Nepal) in south eastern part of Nepal, in Terai (plain with tropical zone ). It has a beautiful artificial lake formed by a kilometer long dam to the north of the Koshi River, which helps to reduce flood damages in the Bihar, a physical state of India.
Due to the marshland of Koshi river and tropical climate, it is very rich in vegetation. The reserve is the home to the wild elephants, the wild water buffalo, deer, Nilgai. The Koshi river itself is home to 80 species of fish including the endangered Gharial crocodile and Gangetic dolphin. Also, it is known as one of the best and finest locations for birdwatching in Asia with more than 500 species of birds, including the globally threatened Swamp Partridge (Francolinus Gularis). The nearby Koshi Barrage has created a vast expanse of water. This makes it the most important staging point for migrating birds, containing 87 winters and trans-Himalayan migratory species. At the same time it is an all year playground for resident ones.
Another most rewarding and greatest asset of the Koshi Tappu Wildlife reserve is, it offers us plenty of nature walking trails. For those with curiosity and perseverance on foot walking is the most profitable way of exploring the meadow, river lagoons and forests. Makalu, the world's fifth highest mountain (8,463m), can be glimpsed on a clear day.
The Koshi Tappu Wildlife Reserve is accessible by air, land and river. It is only a 45 minutes’ flight to Biratnagar from Kathmandu, which is a panoramic flight with the glimpse of Eastern Himalayas, including Mt. Everest (8848m) and Kanchenjunga (8586m). After that we have to catch the bus for one and half hour, to reach there in Koshi Tappu wildlife reserve. Also, we can reach there from ten hours of driving from Kathmandu. It is connecting driving to two major physical regions of Nepal, hilly (mountain) to Terai (Plain) region. So, it provides us greater opportunity to understand the different vegetation, lifestyle and differences between people of those regions. It is so interesting and admirable driving, though, because of the long drive, it may bore and suffocation. If you are adventurous, then rafting will be a perfect alternative. 8-10 days of rafting over Sunkoshi River, brings us here. It is another exciting way to reach and explore the Koshi Tappu wildlife reserve but we need longer vacation and sufficient courage also it is the most costly way to reach there because of camping.
It has mainly three distinct seasons. Summer (February through May) is intensely hot with minimum precipitation. Shade temperatures can reach 400c. The monsoon starts in late May/early June and lasts until September bringing heavy frequent rainfalls with high humidity. Winter through (December to January) is characterized by clear sky and moderate temperature, but can still get quite cold.
The best time to visit is between October to April. In these month,s many migratory and local birds can be sighted.
The best birds in Koshi are: Swamp Francolin, Black-necked Stork, Lesser Adjutant, Comb Duck, Falcated Duck, Spot-billed Duck, Cotton Pigmy Goose, Baer's Pochard, Bailon's Crake, Ruddy Crake, Greater Painted Snipe, Pheasant-tailed Jacana, Yellow-wattled Lapwing, Indian Courser, Black-bellied Tern, Imperial Eagle, White-tailed Eagle, Lesser Kestrel, Bristle Grassbird, Striated Grassbird etc.