The Plain-colored Tanager is extremely active, noisy and restless. It forages mostly in the crowns of trees but moves down lower to feed on fruit. It perches on the catkins to eat Cecropia fruit (Isler and Isler 1987). When eating insects, the Plain-colored Tanager gleans from undersides of bare twigs and branches using the diagonal-lean method. It lowers its head immediately to scan the branch and then moves with quick hops (Slud 1964). It flutters occasionally to catch flying insects, and it sits in the open making short sallies and or occasionally flutter-pursues escaping prey (Isler and Isler 1987).
According to Skutch (1989), these tanagers do not defend any type of territory.
In Costa Rica, Slud (1964) observed possible courtship behavior of three Plain-colored Tanagers. These tanagers were chasing one another among semi-isolated large trees (Isler and Isler 1987). Slud (1964) describes the tanagers as fluttering smoothly and slowly while continuously ticking, and weaving about the leafy branches along established aerial pathways.
Social and interspecific behavior
Plain-colored Tanagers often travel in pairs or in small groups of 3, especially during the breeding season (Hilty and Brown 1986). Occasionally they join small mixed species flocks of tanagers and honeycreepers when foraging (Isler and Isler 1987). They can form groups of 10 or more that move together, often with quick flitting movements of the wings and twitching tails (Wetmore et al. 1984).