There is very little information on the behavior of Fulvous-chinned Nunlet. This species forages in the understory, 1-6 m above the ground (O'Neill 1974, Whittaker and Oren 1999). As do other species of nunlets, this species perches motionless for long periods of time, and can be very confiding, allowing a close approach; it also moves the tail from one side to the other, in a series of 4-5 small jerks (Whittaker and Oren 1999). Prey presumably is captured with a short sally.
There are no published data on territory or home range size for Fulvous-chinned Nunlet.
Undescribed; Fulvous-chinned Nunlet presumably is at least socially monogamous.
O'Neill (1974) described a structure that he suspected was a "type of coursthip accessory" of Fulvous-chinned Nunlet: "On the top of a ridge in open bamboo understory I came upon a structure just above which the presumptive builder, a Nonnula sclateri, perched. At the site of a small sapling with a broken limb that made a 45 degree angle with the ground, the lead litter, composed mostly of bamboo leaves, had been gathered from a 10-inch [25 cm] circle and placed at the center in a neat pile five inches [12.7 cm] in diameter under the angle of the broken limb. The bird would sit on the slanting limb ... ".
Social and interspecific behavior
Fulvous-chinned Nunlets usually are encountered as singles or pairs; only occasionally do they associate with mixed species flocks (Whittaker and Oren 1999).
No reports of predation on Fulvous-chinned Nunlet?