Female Songbirds Learn New Songs Faster Than Male Songbirds
Yale School of Medicine
In the one of the largest learning differences observed between the sexes, a Yale researcher has found that female songbirds learn new songs 60% faster than male songbirds, increasing understanding of how hormones might affect learning.
"The results show that although female and male songbirds are both capable of learning songs, the timing of song acquisition is different depending on gender," said Ayako Yamaguchi, a research associate in the Department of Pharmacology at Yale School of Medicine. "These findings parallel subtle but consistent gender differences in human speech acquisition and offer an opportunity to study the biological basis of sexually distinct learning."
Published in the May 17 issue of Nature, the study compared development of songs in 30 male and female northern cardinals that were raised in an acoustically controlled environment for one year. Yamaguchi found that in northern cardinals, one of a few species in which both sexes sing, females learn a similar number of songs as males in less than one third of the time. Yamaguchi also found that raising cardinals in isolation from conspecific songs lead males to improvise songs, while the same treatment made females essentially mute.
"These findings demonstrate one of the most substantial learning differences between male and female animals found to date," said Yamaguchi, who has long been interested in how male and female animals manage to produce sexually distinct vocalizations.
Vocal imitation is a rare learning skill that evolved only a few times in evolutionary history in humans, whales and birds. This skill allows animals to convert auditory information into motor output. To date, song learning in birds has been studied intensively as a model for understanding human speech acquisition, but very little had been known about song acquisition in female songbirds until now.
A young songbird listens to and memorizes adult songs during a sensitive phase early in life, and later practices its vocalizations until they match the memory formed earlier. To determine the sensitive phase of male and female cardinals, Yamaguchi raised 15 females and 11 males individually in an acoustically controlled environment and tutored them daily with tape-recorded cardinal songs for one year. All the birds heard 40 to 44 song types during that period. She found that the sensitive phase was longer in males than in females, although the number of songs acquired were the same, indicating that females memorized songs faster than males.
Yamaguchi currently conducts research to identify how male and female vocalizations are generated by the central nervous system. This research is in collaboration with Leonard Kaczmarek, professor of pharmacology and physiology at Yale and Darcy Kelley in the Department of biological sciences at Columbia University.
For more information, or to contact Yale School of Medicine, see their website at: info.med.yale.edu/ysm/
|Email Article To A Friend||Link to us!|