Rocko is a pearl pied and I think for sure hes a male he has wing spots and I can kinda see barring on the tail but its not that visible you can only see it if you look closely.Only adult hens and young hatchlings (both sexes) have tail barring. The one exception to this rule is when pied is involved. Sometimes the pied mutation can slow the process of moulting out wing spots and tail bars for males. There are some cases where male pieds can take many years to moult them out.
His pearls are already fading he had alot when he was younger and he sings every morning.Pearl is kind of an odd ball when it comes to tail bars. Some pearls of both sex do not have tail bars at all. The ones that do have altered tail bars that look different. If you think he is a male, send in for a DNA test. Or wait for his pearls to fade which will indicate male. A DNA test will be quicker.
A male will sing loudly in fits a lot especially in the morning. If he does this, he may be male.
I always talk to him and I cant whistle.Birds are quirky and there might not be a sensible reason for it. Maybe he's still just a little bit shy and is holding back on singing to you. If you talk, sing, and/or whistle to him it will encourage him to whistle back.