Volume 28, Issue 5, Pages R204-R205 (March 2018) Black Jacobin hummingbirds vocalize above the known hearing range of birds  Christopher R. Olson, Marcela Fernández-Vargas, Christine V. Portfors, Claudio V. Mello  Current Biology  Volume 28, Issue 5, Pages R204-R205 (March 2018) DOI: 10.1016/j.cub.2018.01.041 Copyright © 2018 Elsevier Ltd Terms and Conditions

Figure 1 Black jacobin vocalizations. (A) Spectrogram of typical three-syllable vocalization recorded with an ultrasonic CM16/CMPA microphone (range 2–107 kHz). (B) Simultaneous recording of the same vocalization as in (A) with a Sennheiser ME66 microphone (range 0.04–20 kHz). Elements in these syllables are above ∼10 kHz, thus well above most background noise (e.g. yellow arrow in B indicates a call by another bird species), and entirely represented by the CM16/CMPA recordings. (C) Magnified view of a single (middle) syllable shows details of harmonic structure; amplitude spectra on the right (grey: averaged over the entire recording; black: measured at the center of the recording) show high energy in F0 and 1st harmonic, the latter within the ultrasound range. The yellow bar between F0 and the first harmonic illustrates the measured region of interrupted periodicity that occurred in all of these syllables. (D) Example of infrequent call type consisting of harmonic stack of descending frequency; amplitude spectra on the right (grey and black as in C) show high energy in F0 and 1st harmonic, both within the human audible range. (E–J) Quantitative analysis based on least-square mean values from Analysis I (see also Table S1). Shown are syllable order effects on F0 (E), peak frequency (F), duration across syllables (G), and duration across inter-syllable intervals (H), as well as behavioral context effects (I) and seasonal effects (J) on entropy. Plotted are least-square means +/- sem. Significant differences between syllables and intervals are indicated by ∗. (K) Black jacobin at feeder (photo by CRO). See Supplemental Information. Current Biology 2018 28, R204-R205DOI: (10.1016/j.cub.2018.01.041) Copyright © 2018 Elsevier Ltd Terms and Conditions