Gartered Trogons consume both arthropods and fruit.
Specimens examined by Weidenfield et al (1985) had stomachs that contained katydids and seeds.
This species has been seen eating the fruits of Gaurea glabra, a species of mahogany tree, in Panama, but infrequently (Howe 1979). Slud (1964) reports that the species sallies for fruits and insects, including large katydids, “always taken during a spread tailed hover”. Stiles et al (1989) reports that they sally and hover to pluck fruit and insects from vegetation. May seize wasps by the wing, including during the pre nest excavation period. Wetmore (1968) reports that one individual had a large ornithopteran in its stomach; another, 2 large caterpillars, 1 large ant, 2 earwigs, and several berries.
Remsen et al (1993) report data from 19 “Trogon violaceous” individuals. The origin of each individual was not described, meaning that these results may apply to individuals that were not Gartered Trogons, so this information should be treated cautiously. They showed the following for stomach contents: 57.9% of individuals had arthropods only; 26.3% had both; 15.8% had fruits only.
The ratio of caeca to intestine is 16.2/100 (Miller 1918). This ratio was published along with ratios from a number of other trogon species to establish what the "normal" ratio for trogons might be. It is unclear exactly how this information might be interpreted, but as other species' caeca lengths may give some indication of how much plant material they consume, perhaps comparing caeca lengths among trogons can help us understand how much of each species' diet is generally composed of tough to digest plant material.