A Japanese friend explained to me... "the plum [is] for courage because the plum puts forth blossoms while the snow is still on the ground."
For some birds, songs are learned by listening to their parents and neighbors during the first year. For other birds, songs are hardwired -- the music is scored in their brains from the beginning. For mockingbirds, singing is a lifetime of choir practice and talent shows, picking up new tunes and modifying old ones.