African gray vs African grey

African gray and African grey both are nouns.

Word	Noun	Adjective	Verb	Adverb
African gray	Yes	No	No	No
African grey	Yes	No	No	No

As nouns, African gray and African grey are synonyms defined as:

African gray and African grey: commonly domesticated grey parrot with red-and-black tail and white face; native to equatorial Africa

Other synonyms of African gray include Psittacus erithacus.

African gray (noun)	African grey (noun)
commonly domesticated grey parrot with red-and-black tail and white face; native to equatorial Africa	commonly domesticated grey parrot with red-and-black tail and white face; native to equatorial Africa