How does Palmer react when the gang tell him they believe he has a pigeon for a pet? What does Palmer want the gang to believe and why?

When his friends protest and suggest he has a pigeon for a pet, Palmer becomes very upset and smashes a soda can to demonstrate what he would do to a pigeon. He tells them he hates pigeons and is ready to wring their necks. He yells at the boys and says "I am going to be the best wringer there ever was!" Palmer is concerned about losing his friends, and he is also concerned that Beans will kill Nipper.