Masked Flowerpiercer makes small, quick hopping movements among the leaves (Isler and Isler 1987). It forages alone, in pairs, and groups of 3-4 of its own species (Isler and Isler 1987). It also regularly associates with mixed species flocks (see Social and interspecific behavior).
Masked Flowerpiercer also probes flowers for nectar (and possibly insects), differing from other flowerpiercers by probing flowers for nectar at the same frequency that it pierces flowers with its beak, making it a legitimate pollinator to some plants (Rojas-Nossa 2007). It gleans foliage as well as making short flights to feed on insects (Hilty 2011).
Masked Flowerpiercers exhibit intraspecific territorial behavior, first establishing territories either alone or in pairs and then defending against other Masked Flowerpiercers with active movement/ displays and hostile songs described as a "rapid, jumbled series of notes" (Moynihan 1963). It has also been reported to show aggressive behavior towards Black-throated Flowerpiercer (Diglossa brunneiventris), Bluish Flowerpiercer (Diglossa caerulescens), and some hummingbird species (Moynihan 1979, Fjeldså and Krabbe 1990).
There is very little information on the sexual behavior of the Masked Flowerpiercer, though they reportedly breed twice a year (Hilty 2011). Masked Flowerpiercer presumably is at least socially monogamous.
Social and interspecific behavior
Masked Flowerpierer forages solitarily, in pairs, and groups of 3-4 of its own species (Isler and Isler 1987). It also regularly associates with mixed species flocks, including species of Hemispingus, Anisognathus, Myioborus, and Myiarchus (Moynihan 1979, Isler and Isler 1987, Ridgely and Greenfield 2001). Its membership in these flocks is noted as varying from a passive follower to an active nuclear member (Moynihan 1979). Moynihan (1963) observed that Masked Flowerpiercers in Quito, Ecuador did not show open hostility towards species such as Glossy Flowerpiercer (Diglossa lafresnayei), Black Flowerpiercer (D. humeralis), and Cinereous Conebill (Conirostrum cinereum), but were territorial against individuals of their own species. In some regions of Venezuela, however, D. cyanea has been observed in aggressive interactions with D. lafresnayii, in which it received attacks, and Bluish Flowerpiercer (D. caerulescens), in which it administered attacks (Moynihan 1979). The overlap in distribution among these species results in high levels of competition. This competition is likely mitigated by the frequency in which each species forages for a particular food source, as well as microgeographical structure (Moynihan 1963). Observations on the microgeographical structure of these communities suggested that Masked Flowerpiercer occupy much higher strata of the forest than other members of Diglossa (Moynihan 1963, 1979).
No reported instances of predation on Masked Flowerpiercer?