Want to attract a female? Sing! But make sure you warble on-key!
That's one of the findings of a new study of male canaries, whose song quality and frequency change with the seasons. The male hormone testosterone plays a role in this changing behavior, and researchers at The Johns Hopkins University wondered how increasing the hormone levels in the bird's brain would affect the song.
They used three groups of birds. One group received a testosterone injection in the POM - the area of the brain that controls sexual motivation, in many animals as well as people. A second group received testosterone throughout the brain. The third group got no treatment.
The first group sang... but not very well. The canaries in the second group performed star-quality vocalizations.
Beau Alward, the study's lead author, explains, "that suggests that testosterone needs to act in different areas of the brain to regulate the specific components of this complex social phenomenon." Those components include the quality of the song as well as the process of courting a female.
Because the hormones in canaries are identical to those in humans, the results of the study could help explain how testosterone acts in the brain to regulate speech and how steroid use affects sexual behaviors. The study appears in the Proceedings of the National Academy of Sciences.