The Grizzled Squirrel Wildlife Sanctuary (GSWS) is located in Virudhunagar and Madurai districts of Tamil Nadu and covers an area 485.2 sq Kms. Over 240+ species of birds are seen in this sanctuary including 14 species of birds endemic to the Western Ghats, such as the critically endangered Oriental white-backed vulture and the long-billed vulture. In addition to grizzled giant squirrels, the sanctuary is home to numerous animals such as barking deer, bonnet macaque, common langur, elephants, flying squirrels, gaur, Indian giant squirrel, leopard, lion-tailed macaques, mouse deer, Nilgiri langur and Nilgiri Tahrs. There are over 220 species of butterflies including many rare and endemic species. Some of the rare butterflies spotted here include Eversheds ace , Silver royal , Orange awlet , Hampsons hedge blue , etc.