[1] His career spanned for more than five decades; de Silva has contributed to the field of zoology with much research and numerous publications particularly on crocodiles, snakes and lizards.
He won two national awards at All Island Magic Competition and conducted massive shows from Matara to Jaffna.
Then he started to rear few non-poisonous snakes, a baby saltwater crocodile, and a few sea turtles in his home, and villagers started calling him Hoony Mahaththaya (Mr Gecko) due to his frequent outings around the village to catch geckos as a food for snakes.
Due to his enormous contribution, de Silva was appointed as the chairman for Declining Amphibian Populations Task Force in the World Conservation Union (now the IUCN) for Sri Lanka.
To create public awareness of reptiles and amphibians, de Silva published the Sri Lanka's first series of posters illustrated with coloured photographs in 1990 and 2001.