Diard's trogon eats caterpillars, beetles, stick-insects, locustids and other Orthoptera, and fruits.

The Dayak Iban community believes that hearing the Diard's trogon's call is a bad omen.

[4] The trogons are birds with colorful plumage that belong to the order Trogoniformes which only comprises one family, the Trogonidae.

As of now, the biogeography of trogons remains unresolved but data analyses strongly suggest they originated from Laurasia.

[3] The adult male has a black head and upper breast paired with a purplish-blue eye ring.

[3] The Diard’s trogon is primarily found in the middle and lower layers of both primary and logged forests within lowland and hilly regions, extending up to an elevation of 900 m in Peninsular Malaysia, while in Thailand, it is encountered at altitudes rarely exceeding 600 m. It is also present in peat swamp forests found in Brunei and Sumatra, highlighting its adaptability to diverse habitats.

Additionally, it can be seen in cocoa plantations located near secondary forest areas, typically at elevations up to 1200 m, although it is usually found at significantly lower altitudes.