Refers to having a pointless debate with somebody utterly
ignorant of the subject matter, but standing on a dogmatic position that cannot be moved with any amount of education or
logic, but who always proclaims victory.
Origin:
"Debating creationists on the topic of evolution is rather like trying to play
chess with a pigeon; it knocks the pieces over, craps on the board, and flies back to its flock to claim victory." -- Scott D. Weitzenhoffer (From an Amazon.com book review)
Man, trying to explain to those moon landing deniers that the Apollo program was real is like playing pigeon
chess -- all they do is knock the pieces over and
crap on the board.