Song lateralization in the zebra finch.

The neural mechanisms for bird song commonly are lateralized, depending greatly on the integrity of the left song system and responding much less to manipulations of the system on the right. These results suggest that it is advantageous for the mechanisms controlling song to be lateralized and in this direction. In this context, it is of special interest to study likely exceptions to these rules, for the light they can shed on the functions and mechanisms of song lateralization. Accordingly, we have tested the extent and manner of song lateralization in the zebra finch (Taeniopygia guttata), a species previously identified with an atypical pattern of lateralization. Song by male finches was observed before and after sham operations or transections of the left or right tracheosyringeal nerve. Sham operations failed to affect song. In contrast, males with cuts of the right nerve experienced a depression in fundamental frequency to an apparent baseline of approximately 500 Hz. This effect is consistent with the dominance of the right song system in zebra finches. On the other hand, males with cuts of the left nerve also showed consistent changes, exhibiting frequency increases, especially toward the ends of syllables. The source of these changes is not completely clear. However, rather than challenging the emerging view of lateralization in zebra finches, they may reflect a combination of right dominance and an atypical mechanism for the gating of syringeal airflow and vocalization during song.