Who's the boss?

A man goes into a pet shop to buy a parrot. The shop owner points to three identical-looking parrots on a perch and says: "The parrot on the left costs $500." "Why does the parrot cost so much?" asks the customer. The owner says "Well, the parrot knows how to do legal research."

The customer then asks about the next parrot, to be told that this one costs $1,000 because it can do everything the other parrot can do plus it knows how to write a brief that will win any case.

Naturally, the increasingly startled customer asks about the third parrot, to be told that it costs $4,000. Needless to say, this begs the question, "What can it do?" To which the owner replies, "To be honest, I've never seen him do a damn thing, but the other two call him Senior Partner."