The principal birds are the peacock, jungle fowl and black partridge, while migratory duck and geese swarm on the ponds and lakes and big rivers of Terai. Terai forests are full of jasmin, minosa, accecia reeds and bamboo. Great rivers such as the Karnali, Narayani, and Sapta Koshi flow through this area into the broad plains of the Terai. This zone also includes the so-called middle hills which extend northwards in a somewhat confused maze of ridges and valleys to the foot of the great Himalayas. Among the tree species characteristic of this region are Castenopsis indica in association with Schima wallichii, and other species such as Alnus nepalensis, Acer oblongum and various species of oak and rhododendron which cover the higher slopes where deforestation has not yet taken place.
Orchids clothe the stems of trees and gigantic climbers smother their heads.
The variety and abundance of the flora and fauna increase progressively with decreasing altitude and increasing luxurance of the vegetation. This zone is generally poor in wildlife. The only mammals, which are at all widely distributed, are wild boar, barking deer, serow, ghoral and bears. Different varieties of birds are also found in this zone. Different varieties of birds are also found in this zone.