Kathmandu, October 26 With the onset of winter season, winter migratory birds have started arriving in Nepal to avoid freezing cold in the Northern hemisphere. Many of such birds can be easily seen in the wetland areas, including Chovar and Taudaha of Kathmandu valley and southern plains during winter season, according to officials of Department of National Parks and Wildlife Conservation. Mid-September to late October is considered the peak migration time for such birds, however migration can continue till the end of November. More than 150 species of winter migratory birds from China, Mongolia, Korea, Siberian region of Russia and central Asia come to the southern plains with the beginning of winter. Ram Dev Chaudhary, an ecologist at the DoNPWC also an expertise in bird conservation programme, said there were two kinds of migratory birds that came to the country — wetland birds and terrestrial birds. The terrestrial birds can also be divided into two sub groups — forest birds and grassland birds. Most of the birds that migrate to Nepal belong to duck species like mallard, ruddy shelduck, and gadwall. Eurasian teal, green shank, thrushes, fly catcher, booted eagle are other migratory birds that come to Nepal during winter. According to ornithologists, some of these birds fly up to 9,375 metres and weigh up to 2.5 kg. Ecologist Chaudhary said these birds travelled long distance, especially to avoid cold and for breeding. Programme officer at Bird Conservation Nepal Jyotendra Thakuri said the number of migratory birds had decreased by 75 per cent over the past 10 to 15 years inside Kathmandu valley. “The number is still declining rapidly due to increasing urbanisation in the valley and destruction of wetlands and forest areas,” he shared. Meanwhile, many summer migratory birds from as far as Sub-Saharan Africa, South-east Asia and South India come to Nepal in search of comparatively less hotter areas. Ornithologists claim that many species of summer migratory birds travel more than 5,000 km to come to Nepal.