wader vs aquatic bird

wader and aquatic bird both are nouns.

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

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

wader: any of many long-legged birds that wade in water in search of food
aquatic bird: wading and swimming and diving birds of either fresh or salt water

wader (noun)	aquatic bird (noun)
any of many long-legged birds that wade in water in search of food	wading and swimming and diving birds of either fresh or salt water