jail bird vs felon

jail bird and felon both are nouns.

Word	Noun	Adjective	Verb	Adverb
jail bird	Yes	No	No	No
felon	Yes	No	No	No

As nouns, felon is a hypernym of jail bird; that is, felon is a word with a broader meaning than jail bird:

jail bird: a criminal who has been jailed repeatedly
felon: someone who has committed a crime or has been legally convicted of a crime

Other hypernyms of jail bird include criminal, crook, malefactor, outlaw.

jail bird (noun)	felon (noun)
a criminal who has been jailed repeatedly	someone who has committed a crime or has been legally convicted of a crime
	a purulent infection at the end of a finger or toe in the area surrounding the nail