for the adjoining human settlements and helps in maintaining the environmental balance. Wildlife It is home of many endangered species. The vertebrate fauna includes, besides a number of fishes, about 34 species of mammals, about 166 species of birds including migratory land and water birds, about 36 species of reptiles and about 4 species of amphibia. This sanctuary is notable for its wealth of birds and is indeed a bird watcher’s paradise. The zoological values of this sanctuary are briefly given below. Invertebrates This sanctuary is the abode of, besides innumerable other insect species, about 49 butterfly species belonging to 9 families; the most prominent include the common rose, common Mormon, lime butterfly, common sailor, common Indian crow and black rajah. Mammals Nearly 34 – species of mammal belonging to about 8 natural orders and 16 families are seen in this sanctuary, out of which about 14 species are of endangered status, namely the tiger, Indian leopard, jungle cat, small Indian civet, Asian palm civet, Indian wolf, golden jackal, sloth bear, honey badger, Indian giant flying squirrel, gaur, four-horned antelope, spotted deer, sambar deer, nilgai, Indian spotted chevrotain and Indian pangolin. Birds The avifauna of this sanctuary is its most attractive wildlife feature. Well over 166 species belonging to about 16 different orders and 47 families have been recorded here. Also as many as 15 species of migratory birds and about 42 species of local migrants are reported. One remarkable bird, the bar-headed goose, is a winter migrant from Ladakh and Tibet and inhabits Chorkhamara tank located adjoining the sanctuary. There are 13 bird species of endangered status including Indian peafowl and the birds belonging to the family Accipitridae. Reptiles This sanctuary is the abode of about 36 species of reptiles belonging to 2 natural orders and 11 families out of which about 6 species are of endangered status namely Indian rock python, dhaman, Indian cobra, Russell’s viper, checkered keelback and Bengal monitor. Amphibia This sanctuary is a home of many interesting varieties of frogs and toads like tree frogs, bull frogs, six-toed frogs, and an uncommon toad, Uperodon montanus. Fishes The Nagzira lake and the other water-bodies in and around this sanctuary abound in many varieties of fresh water fishes. Bio-geographic zonation As per the Biogeography classification adopted by Wildlife Institute of India, Dehradun, this sanctuary is classified as follows. i) Bio-geographic Kingdom - Paleotropical ii) Sub Kingdom -