aquatic bird vs wader

aquatic bird and wader both are nouns.

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

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

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

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