[1] On leaving school Trounson worked for several years in the hardware department of the family business, following which he became a management trainee with Marks and Spencer.
[1] Trounson was commissioned into the Royal Army Service Corps (RASC) as a second lieutenant on 2 December 1939, shortly after the outbreak of the Second World War.
After three years, during his mid-tour leave, he travelled with Peggy through Queensland recording and photographing birds, producing pictures of 110 species.
His success resulted in further expeditions, to the Cape York Peninsula, Iron Range, and the Simpson Desert where he photographed the Eyrean grasswren, unseen since the 19th century and thought to be possibly extinct.
[1] On 26 January 2003, Trounson was awarded the Medal of the Order of Australia (OAM) "for service to the community as creator of the National Photographic Index of Australian Birds".