Environmentally dependent sensitive periods for avian vocal learning

Abstract

Experience during brief periods of development can exert a profound influence on later life1. Among songbirds, experimental evidence for enhanced vocal learning during a relatively brief period early in life is well documented2,3. The timing of vocal learning with respect to dispersal is fundamental to our understanding of many population processes, yet the significance of the sensitive period remains unclear. We report here that in our study of the marsh wren (Cistothorus palustris), a North American songbird, we found that the sensitive period for song learning is not rigidly programmed with respect to dispersal and/or migration; two environmental factors, the photoperiod and the amount of adult song heard during the hatching year, influence the nature of the sensitive period during the hatching year, the ability to learn further the next spring, and the relative dates at which young males develop their adult songs.