anseriform bird vs water bird

anseriform bird and water bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
anseriform bird	Yes	No	No	No
water bird	Yes	No	No	No

As nouns, water bird is a hypernym of anseriform bird; that is, water bird is a word with a broader meaning than anseriform bird:

Other hypernyms of anseriform bird include waterbird, waterfowl.

anseriform bird (noun)	water bird (noun)
chiefly web-footed swimming birds	freshwater aquatic bird