pelecaniform seabird vs seafowl

pelecaniform seabird and seafowl both are nouns.

Word	Noun	Adjective	Verb	Adverb
pelecaniform seabird	Yes	No	No	No
seafowl	Yes	No	No	No

As nouns, seafowl is a hypernym of pelecaniform seabird; that is, seafowl is a word with a broader meaning than pelecaniform seabird:

pelecaniform seabird: large fish-eating seabird with four-toed webbed feet
seafowl: a bird that frequents coastal waters and the open ocean: gulls, pelicans, gannets, cormorants, albatrosses, petrels, etc.

Other hypernyms of pelecaniform seabird include sea bird, seabird.

pelecaniform seabird (noun)	seafowl (noun)
large fish-eating seabird with four-toed webbed feet	a bird that frequents coastal waters and the open ocean: gulls, pelicans, gannets, cormorants, albatrosses, petrels, etc.