seafowl vs sea bird

seafowl and sea bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
seafowl	Yes	No	No	No
sea bird	Yes	No	No	No

As nouns, seafowl and sea bird are synonyms defined as:

seafowl and sea bird: a bird that frequents coastal waters and the open ocean: gulls, pelicans, gannets, cormorants, albatrosses, petrels, etc.

Other synonyms of seafowl include seabird.

seafowl (noun)	sea bird (noun)
a bird that frequents coastal waters and the open ocean: gulls, pelicans, gannets, cormorants, albatrosses, petrels, etc.	a bird that frequents coastal waters and the open ocean: gulls, pelicans, gannets, cormorants, albatrosses, petrels, etc.