I'm reading some 1948 strips from the comic "Pogo". In a dialogue I found the sentence
"You gone whup the opposition like they is ol' tilly birds!"
Easy-to-understand intentional mispronunciations aside (people who read "Pogo" know the characters speak in a, let's say, strange way), I can't seem to find any meaning for the word "tilly" apart from the first name, which I think isn't appropriate here.
The context is the election of a new sheriff for the swamp the characters live in (which mocks the real-life U.S. presidential elections of 1948, where Truman won).
Can the word be related to a political pun? Or simply a modification of "little" or "tiny" or "silly"? Or is there a kind of bird called "tilly bird"?