waterbird vs screamer

waterbird and screamer both are nouns.

Word	Noun	Adjective	Verb	Adverb
waterbird	Yes	No	No	No
screamer	Yes	No	No	No

As nouns, screamer is a hyponym of waterbird; that is, screamer is a word with a more specific, narrower meaning than waterbird:

waterbird: freshwater aquatic bird
screamer: gooselike aquatic bird of South America having a harsh trumpeting call

Other hyponyms of waterbird include anseriform bird.

waterbird (noun)	screamer (noun)
freshwater aquatic bird	a very hard hit ball
	gooselike aquatic bird of South America having a harsh trumpeting call
	a sensational newspaper headline
	someone who communicates vocally in a very loud voice