red grouse vs moor-bird

red grouse and moor-bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
red grouse	Yes	No	No	No
moor-bird	Yes	No	No	No

As nouns, red grouse and moor-bird are synonyms defined as:

red grouse and moor-bird: reddish-brown grouse of upland moors of Great Britain

Other synonyms of red grouse include Lagopus scoticus, moorbird, moorfowl, moorgame.

red grouse (noun)	moor-bird (noun)
reddish-brown grouse of upland moors of Great Britain	reddish-brown grouse of upland moors of Great Britain