Fig. 1.

Temporal–sequential structure of birdsong. (A) Spectrogram (power at frequency vs. time) of a Bf song segment, with letter labels assigned to unique syllables. Adult Bf song typically consists of 5–12 unique syllables produced in probabilistic sequences. (B) Forward transition diagram of song syntax, compiled from many renditions of the song in A. Each node corresponds to a unique syllable from the bird’s repertoire. Edges between nodes denote transitions between syllables obtained from a large corpus of songs (dots denote transition destination). The width of each edge corresponds to the observed probability of transitioning from a syllable to any other syllable. (C) Intersyllable gap (ISG) probability distributions for all transitions in this bird. Each distribution is presented as the Gaussian fit to the log₁₀ ISG data.