വിജയന്‍) (born 29 May 1945) is an Indian environmentalist, wildlife biologist, ornithologist, an admirer of naturopathy and the founding Director of the Salim Ali Centre for Ornithology and Natural History.

He obtained Ph.D. in Field Ornithology in 1976 from the University of Bombay for his work on the Ecological isolation in bulbuls (Class Aves, family Pycnonotidae) with special reference to Pycnonotus cafer (L) and Pycnonotus luteolus (Lesson) at Point Calimere, Tamil Nadu under the guidance of Salim Ali.

[6] As the founder Director of the Salim Ali Centre for Ornithology and Natural History, the premier ornithology institute in the country, he led several studies for the conservation of threatened bird of India.

[7] He was instrumental in developing the Pupil's Biodiversity Register for each Grama Panchayath in the state of Kerala.

[9] Member: Western Ghats Ecology Expert Panel (WGEEP) known as Gadgil Committee, Chairman: Kerala State Biodiversity Board, Director (1991-2005): Salim Ali Centre for Ornithology and Natural History, Officer on Special Duty (1990): Salim Ali Centre for Ornithology and Natural History, Senior Scientist (1987-1990): Bombay Natural History Society, Project Scientist (1981-1987): Bombay Natural History Society, Member (1980-1984): Senate of Calicut University, Member (1979-1983): Kerala State Wildlife Advisory Board, Member (1979 1982): IUCN's Asian Elephant Specialist Group, Wildlife Biologist and Head of Division of Wildlife Biology (1977-1981): Kerala Forest Research Institute, Research Assistant (1976-1977): Kerala Forest Research Institute, Research Associate (1976): Bombay Natural History Society, Visiting Scientist (1975-1976): Indian Institute of Science, Bangalore, Salim Ali-Loke Wan Tho Research Fellow (1972 75): Bombay Natural History Society, Research Assistant (1969 71): Bombay Natural History Society.