long-legs vs shore bird

long-legs and shore bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
long-legs	Yes	No	No	No
shore bird	Yes	No	No	No

As nouns, shore bird is a hypernym of long-legs; that is, shore bird is a word with a broader meaning than long-legs:

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

Other hypernyms of long-legs include limicoline bird, shorebird.

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