During his career he had become an expert in the region's ornithology which he put to use preparing a monumental reference work, The Birds of the Malay Peninsula.
[3] When the Pacific War broke out, the British authorities in Singapore established a Department of Information with Victor Purcell, previously the government's Protector of Chinese, as Director-General.
Purcell accepted the offer and Chasen became his personal assistant, valued for his training and experience in the organisation of exhibitions.
[4] His work for the Department of Information meant that Chasen was evacuated on one of the last boats leaving the doomed colony.
[5] Frederick Nutter Chasen is commemorated in the scientific name of a venomous snake native to Borneo, Garthius chaseni.