Song learning in Varied Tits Poecile varia: sensitive period and the effects of night-sleep

Capsule: Varied Tits Poecile varia learned vocalizations in the first few weeks of their life. Night-sleep affected the development of vocal learning in Varied Tits.

Aims: We aimed to quantify the sensitive period of song learning and to examine the effects of sleep on song development in Varied Tits, an endemic forest songbird in East Asia.

Methods: Song development in Varied Tits was investigated in the first 90 days following hatching. The effect of night-sleep on birdsong learning was examined by analysing and comparing the song structure in the evening and the next morning.

Results: We found that most individuals began to sing a subsong from 15 days of age and acquired mature song at about 53 days. The sensitive period of song learning in Varied Tits was from 25 to 53 days after hatching. There were significant and positive correlations between maximum frequency and vocal changes before and after night-sleep.

Conclusion: Our findings uncover the timings and processes of song development, and highlight the importance of the sensitive period in birdsong development in wild birds.