Zebra finches memorize a song during a critical period somewhere after post-hatching day (PHD) 25. They then progressively form their own song through a sensorimotor process of matching their own vocal output with the stored memory of the tutor song. Here we show that early testosterone treatment induces premature song development. This premature singing activity involves all forebrain control region as judged from expression of the immediate early gene ZENK while the direct connection between HVC and RA of the descending song control pathway is not yet functional. The young testosterone males were exposed to the tutor song only until PHD 25 but were nevertheless able to produce copies of the tutor song in adulthood in difference to males that were not exposed to a tutor or exposed to a tutor but not treated with testosterone. The prematurely singing males show signs of sensory-motor leaning only after PHD 35 when the HVC-RA synapse is formed. Thus testosterone advances the sensitive period for song sensory learning while sensorimotor learning requires the direct synaptic connection between HVC and RA.