(not) a dicky bird
(Not) anthing at all. We've had him detained for four hours, but he won't say a dicky bird to us about his involvement in the robbery. We heard not a dicky-bird out of the kids all night—they were quiet as can be.
not a dicky bird
not a word; nothing at all. informal Dicky bird is rhyming slang for ‘word’.
1988 Glenn Patterson Burning Your Own Sammy put his ear to where he thought its heart ought to be: not a dickybird.