tropic bird vs boatswain bird

tropic bird and boatswain bird both are nouns.

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

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

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

Other synonyms of tropic bird include tropicbird.

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