As the name flycatcher suggests, the Nimba flycatcher is insectivorous. Its prey ranges from small beetles and caterpillars to social insects such as ants, which make up a large proportion of its diet (2).
The Nimba flycatcher lives in pairs or in groups of three to six individuals. It lives in the canopy up to 50 metres above the ground, rarely being found below 20 metres. The group moves slowly through the canopy, spending a lot of time perched motionless in-between foraging, and typically remains in one location for a few days before moving on (2).
Hunting comprises infrequent flights, in which the flycatcher dives below its perch to ambush prey, or flies in an upward rally, rapidly seizing insects on the undersides of leaves and branches. In addition, the Nimba flycatcher will seek out insects in mossy fissures and cracks, running with its head low and grabbing prey as it moves (2).
Not much is known about the breeding behaviour of this rare bird. However, the female has been observed with enlarged ovaries around July to August in Liberia (2).