Bhutan has been identified as one of the 10 bio-diversity hotspots in the world, harbouring an estimated 770 species of birds which includes the plumage, the Himalayan griffen, the unique high- altitude wader, the ibisbill, the spectacular hornbill, barbets, sunbirds, fulvattas, yuhinas, cuckoos, and many more. The country also has a great variety of endangered species like the black- necked crane, the monal pheasant, peacock pheasant, raven and the Rufous- necked hornbill. Along its southern border, the narrow tropical and subtropical belt supports the Asiatic elephant, greater one-horned rhinoceros, gaur, wild water buffalo, hog deer, tiger, clouded leopard, hornbill, trogon and other mammals and birds characteristic of indomalayan species. Only 150 kilometers to the north, high Himalayan fauna include the blue sheep, takin, musk deer, snow leopard, wolf and other species characteristic of the Palearctic realm. Bhutan is also known for its wintering populations (about 350 birds) of the vulnerable black-necked crane in the valleys of Phobjikha, Bomdeling and Gyetsa.