Developmental influences on auditory perception in female zebra finches - is there a sensitive phase for song preference learning?

Song plays an important role in mate choice in oscine songbirds. Male advertising song is culturally transmitted resulting in individual- or population-specific song variants. Evidence is accumulating that female song preferences are influenced by those song variants they experienced when young, but the nature and timing of the acquisition process itself is still poorly understood. Song acquisition (as well as sexual imprinting) has been studied in more detail in zebra finches (Taeniopygia guttata) than in any other songbird species, making it timely to review the consequences of early exposure on female song perception in this species. The current literature provides substantial evidence not only for preference learning but also for exposure-dependent perceptual fine-tuning. Sensitivity for song preference learning changes over the course of development. Preference teaming does not seem to occur earlier than 25 days of age (hence paralleling the time course for song acquisition in males), but a potential endpoint is currently less obvious. However, studies so far have focussed on the outcome rather than the process of learning, and thus have not aimed at delineating a sensitive phase. Early acquired song preferences seem highly stable regardless of additional experience, which suggests a self-terminating process as previously found for sexual imprinting. There are still obvious gaps in our understanding of the mechanisms underlying the process of song preference learning, but these seem worthwhile addressing, as the consequences for mate choice might differ dramatically depending on when and from whom learning takes place.