grey catbird vs catbird

grey catbird and catbird both are nouns.

Word	Noun	Adjective	Verb	Adverb
grey catbird	Yes	No	No	No
catbird	Yes	No	No	No

As nouns, grey catbird and catbird are synonyms defined as:

grey catbird and catbird: North American songbird whose call resembles a cat's mewing

Other synonyms of grey catbird include Dumetella carolinensis, gray catbird.

grey catbird (noun)	catbird (noun)
North American songbird whose call resembles a cat's mewing	North American songbird whose call resembles a cat's mewing
	any of various birds of the Australian region whose males build ornamented structures resembling bowers in order to attract females