Fig. 5. Unilaterally produced subharmonics and deterministic chaos (mockingbird m152). (A) Arrows indicate abrupt transitions from a harmonic vocalization to a chaotic sound. The chaotic region is followed by a period of subharmonics (arrow b) after which the vocalization returns to a periodic state. (B) A 25 ms segment of the sound waveform. The arrow indicates an abrupt transition from a periodic to aperiodic oscillation. (C) Power spectrum taken at arrow b (spectrogram, A). Spectral peaks show sound energy at f₀ and associated harmonics (2f₀, 3f₀, etc) as well as at 0.5f₀ and related harmonics (1.5f₀, 2.5f₀, 3.5f₀, etc.) Abbreviations as in Fig. 3.