A parrot was in a cage in a pet shop with a string attached to each leg.
A man walked in looking to buy a pet, so the shopkeeper came over and started to try and sell him a dog when the man noticed the parrot.
He asked what the strings were for and the shopkeeper replied, “Well, if you pull the right string the parrot says, ‘Polly wanna cracker’. If you pull the left string it says, ‘my name’s Sam’“.
The man being of inquisitive nature tried both and thought it was really neat, but was still curious.
So he asked what would happen if he pulled both strings, the parrot piped up, “I’d fall off the perch you idiot!”
This joke is included in the Black Book of Jokes. You can order it from here.