boatswain bird vs tropicbird

boatswain bird and tropicbird both are nouns.

Word	Noun	Adjective	Verb	Adverb
boatswain bird	Yes	No	No	No
tropicbird	Yes	No	No	No

As nouns, boatswain bird and tropicbird are synonyms defined as:

boatswain bird and tropicbird: mostly white web-footed tropical seabird often found far from land

Other synonyms of boatswain bird include tropic bird.

boatswain bird (noun)	tropicbird (noun)
mostly white web-footed tropical seabird often found far from land	mostly white web-footed tropical seabird often found far from land