Contrary to popular belief, Chilika, Asia's largest brackish water lake, continues to be a biologically healthy wet land. Ornithologist and wildlife experts say that the richness of species and avian diversification are the indexes of a biologically healthy wet land, which Chilika is, not the number of birds visiting per year.According to wildlife expert and ornithologist Sushanta Das, over 20 lakh birds visited Chilika in 1997-98, as per the recent report of the status survey, conducted in Chilika as on February 15. Out of these, nearly 50 per cent of the winged visitors were concentrated in the Nalabana bird sanctuary and the rest on its outskirts.