oystercatcher vs shore bird

oystercatcher and shore bird both are nouns.

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

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

oystercatcher: black-and-white shorebird with stout legs and bill; feed on oysters etc.
shore bird: any of numerous wading birds that frequent mostly seashores and estuaries

Other hypernyms of oystercatcher include limicoline bird, shorebird.

oystercatcher (noun)	shore bird (noun)
black-and-white shorebird with stout legs and bill; feed on oysters etc.	any of numerous wading birds that frequent mostly seashores and estuaries