Pet Store Parrots

A guy walks into a pet store wanting a parrot. The store clerk shows him two beautiful ones out on the floor.
"This one's $5,000 and the other is $10,000." the clerk said.
"Wow! What does the $5,000 one do?"
"This parrot can sing every aria Mozart ever wrote."
"And the other?" said the customer.
"This one can sing Wagner's entire Ring cycle. There's another one in the back room for $30,000."
"Holy moly! What does that one do?"
"Nothing that I can tell, but the other two parrots call him 'Maestro'."