shore bird vs longlegs

shore bird and longlegs both are nouns.

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

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

shore bird: any of numerous wading birds that frequent mostly seashores and estuaries
longlegs: long-legged three-toed black-and-white wading bird of inland ponds and marshes or brackish lagoons

shore bird (noun)	longlegs (noun)
any of numerous wading birds that frequent mostly seashores and estuaries	long-legged three-toed black-and-white wading bird of inland ponds and marshes or brackish lagoons