SONG LATERALIZATION IN THE ZEBRA FINCH

The neural mechanisms for bird song commonly are lateralized, dependin g greatly on the integrity of the left song system and responding much less to manipulations of the system on the right. These results sugge st that it is advantageous for the mechanisms controlling song to be l ateralized and in this direction. In this context, it is of special in terest to study likely exceptions to these rules, for the light they c an shed on the functions and mechanisms of song lateralization. Accord ingly, 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 depres sion in fundamental frequency to an apparent baseline of approximately 500 Hz. This effect is consistent with the dominance of the right son g system in zebra finches. On the other hand, males with cuts of the l eft nerve also showed consistent changes, exhibiting frequency increas es, especially toward the ends of syllables. The source of these chang es is not completely clear. However, rather than challenging the emerg ing view of lateralization in zebra finches, they may reflect a combin ation of right dominance and an atypical mechanism for the gating of s yringeal airflow and vocalization during song. (C) 1997 Academic Press .