Singing experience–dependent regulation for the sensorimotor learning period of song acquisition in zebra finch.

(A) Critical period of vocal learning (upper panel) and song development (lower panels) in the zebra finch. Blue bars in the lower panels represent the motif structure of crystallized song. Scatter plots indicate the distribution of 500 syllables (duration versus pitch). (B) Examples of songs of SP birds at 1–2 days after release at adult age (100–101 phd). (C) Comparison of syllable acoustic features, pitch, pitch goodness, AM, and entropy variance between normally reared juveniles (n = 5, 40–50 phd), normal adults (n = 5, 100–104 phd), SP birds after release (n = 5, 100–103 phd), and SP birds after song crystallization (n = 5, 119–126 phd). *p p t test. (D) Song development of an SP bird after release at adult age. Blue bars indicate the motif structure of crystallized song. (E, F) Comparison of mean syllable and motif similarities against tutor song between SP birds after release (n = 5, 100–103 phd) and after song crystallization (n = 5, 119–126 phd) and singing-persistent birds (n = 3, 101–105 phd. ***p t test. NSp > 0.05; unpaired t test. Supporting data can be found in S1 Data. AM, amplitude modulation; NS, not significant; phd, post hatching day; SP, singing-prevented.