wading bird vs wader

wading bird and wader both are nouns.

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

As nouns, wading bird and wader are synonyms defined as:

wading bird and wader: any of many long-legged birds that wade in water in search of food

wading bird (noun)	wader (noun)
any of many long-legged birds that wade in water in search of food	any of many long-legged birds that wade in water in search of food