Silent Valley National Park is situated in the Kundali Hills, along the Western Ghats. This park is surrounded by the Nilgiri Forests in the north and Nilambur Forests in the south. The Palghat Forests and Attappadi Reserve Forests are located on the western and eastern side of the park, respectively. This park is located at an average elevation of around 3600 ft above sea level. It provides a home to different animals like elephants, tigers and lion-tailed macaques. This park was threatened in the 1970's due the construction of a Hydel Power Project. Environmentalists protested on a wide scale and it led to the re-notification of the Silent Valley. Afterwards, it was raised to the status of a National Park in 1984. Later in 1986, the park was included in the Nilgiri Biosphere Reserve as its core area. This national park is home to 34 species of mammals, more than 150 species of birds and about 200 species of butterflies. Around 1000 species of flowering plants are found in the park, out of which, about 110 species belong to the family of orchids. Over 400 species of moths and 128 species of beetles can be spotted in the forest area. River Kunthi that originates from the Nilgiri Hills flows through the forest. The Nilgiri wood-pigeon, Malabar parakeet, grey-headed bulbul, broad-tailed grassbird, rufous babbler and white-bellied shortwing are some of the resident birds of this park. The park is inhabited by the great Indian hornbill, which is counted among the rare and endangered bird species of India. One can also spot tigers, leopards, sambar, wild boars and gaur.