Mistletoe Tyrannulet moves fairly rapidly through vegetation, searching very actively for food, with the tail often held straight out or upward. The behavior generally is "lively and animated", and this tyrannulet often stands "with legs seemingly extended to maximum extent with the tail cocked" (Stiles and Skutch 1989). Mistletoe Tyrannulet forages at all levels of the forest, but primarily in the middle and high canopy.
Typically encountered singly or in pairs. There are no published data on territorial defense, maintenance, or fidelity, or on home range size, for Mistletoe Tyrannulet.
Undescribed; Mistletoe Tyrannulet presumably is at least socially monogamous.
Social and interspecific behavior
Mistletoe Tyrannulet tends to be solitary except when nesting. Skutch (1960) observed the male defending the nesting site from other, larger species, such as Olivaceous Woodcreeper Sittasomus griseicapillus and Golden-hooded Tanager Stilpnia larvata, while the female constructed the nest or incubated.
No reports of predation on Mistletoe Tyrannulet.