In many species of birds, males sing to court females and to defend territories or nest sites, whereas females sing little, if at all. This behavioural sex difference is paralleled by sexual dimorphisms in neural and peripheral structures involved in song production. In adulthood, singing is generally activated by gonadal steroids, such as testosterone, but the role that these hormones play in the natural development of the structural and functional sex differences is at present an intriguing mystery.
Keywords: zebra finch; oestrogen; canary; aromatase; sex difference







