Territorial male Scintillant Hummingbirds do not sing undirected song from a perch. Males and (possibly females) do produce at least three types of vocalizations. Two are generated during agonistic interactions; the third is uttered by both sexes both in the presence and apparent absence of other hummingbirds, and has an unknown function. (see spectograms in Clark et al 2011).
Like all hummingbirds, Scintillant Hummingbirds have a wingbeat frequency high enough that humans perceive the pressure fluctuations of the wings as a humming sound.
Additionally, male Scintillant produce four types of sonations. First, during ordinary flight a wing trill is produced by the emarginated, narrowed outer primary (P10) (see spectrogram). During the shuttle display (see Sexual Behavior), duplets of wing trill are alternated with duplets of another broadband sound (see spectogram) that is produced by an unknown mechanism of wing-feathers (Clark et al. 2011).
Males also perform a second courtship display, the display dive. During the dive the wing trill is produced, as well as a second trill termed ‘trill 2’ by Clark et al. (2011). Trill 2 is likely a sonation because its trill rate matches the wingbeat frequency. Finally, an additional pulsed sound is produced in 2 to 4 short bursts at the bottom of the dive. This sound, which consists of a low fundamental (0.3 kHz) and a stack of many (>20) harmonics, is produced by rectrix #2 (R2) of the tail, which is emarginated (Clark et al. 2011). The Volcano and Broad-tailed (Selasphorus platycercus) hummingbirds produce a similar sound with similarly emarginated R2’s; the sound is considerably quieter in the Scintillant as compared to these relatives (Clark et al. 2011).