Extended Data Fig. 2 |. Examples of canary song phrase sequences, rare inter-phrase gaps, and aberrant syllables.

a. Additional spectrograms of phrase sequences (colors above the spectrograms indicate phrase identity), leading to a repeating pair of phrases (pink and yellow). b. Examples of flexible phrase sequencing comprised of pitch changes (from bird #3). c. Examples of phrase transitions with a pitch change from bird #2. d-f. Phrase sequences showing changes in spectral and temporal parameters. d, bird #1, changes from up sweep (purple) to down sweep (dark red) through intermediate phrases of intermediate acoustic structure. e, bird #1, a change in inter-syllable gaps. f, from bird #2, changes in pitch sweep rate. g. Top and bottom sonograms compare the same phrase transitions where the inter-phrase gap varies. h, i. The top sonogram includes a rare vocalization in the beginning of the 2nd phrase (highlighted) that, in panel i, resemble the onset of an orange phrase type.