rover vs bird of passage

rover and bird of passage both are nouns.

Word	Noun	Adjective	Verb	Adverb
rover	Yes	No	No	No
bird of passage	Yes	No	No	No

As nouns, rover and bird of passage are synonyms defined as:

Other synonyms of rover include roamer, wanderer.

rover (noun)	bird of passage (noun)
someone who leads a wandering unsettled life	any bird that migrates seasonally
an adult member of the Boy Scouts movement	someone who leads a wandering unsettled life