Fig 2. Temporal structure of vocal behavior.

(A) Schematic showing the intermittent occurrence of vocally active periods (VAPs, black bar) at sporadic intervals throughout the first hour of a multiple-hours-long continuous recording session of one male zebra finch (z007). (B) Zoomed-in view of one 25-second-long VAP comprising several bouts, denoted by light-blue rectangles above the sound pressure waveform and corresponding spectrogram. (C) Zoomed-in view of the first bout in segment (B) showing introductory notes, typically repeated a variable number of times prior to the start of the bout and labeled as “’; other vocalizations not part of the courtship song, labeled ‘C’; and syllables comprising the courtship song, labeled ‘1’, ‘2’, ‘3’, ‘4’, and ‘5’, based on their sequential order in the motif.