wader vs shore bird

wader and shore bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
wader	Yes	No	No	No
shore bird	Yes	No	No	No

As nouns, shore bird is a hyponym of wader; that is, shore bird is a word with a more specific, narrower meaning than wader:

wader: any of many long-legged birds that wade in water in search of food
shore bird: any of numerous wading birds that frequent mostly seashores and estuaries

wader (noun)	shore bird (noun)
any of many long-legged birds that wade in water in search of food	any of numerous wading birds that frequent mostly seashores and estuaries