dark-eyed junco vs Junco hyemalis

dark-eyed junco and Junco hyemalis both are nouns.

Word	Noun	Adjective	Verb	Adverb
dark-eyed junco	Yes	No	No	No
Junco hyemalis	Yes	No	No	No

As nouns, dark-eyed junco and Junco hyemalis are synonyms defined as:

dark-eyed junco and Junco hyemalis: common North American junco having grey plumage and eyes with dark brown irises

Other synonyms of dark-eyed junco include slate-colored junco.

dark-eyed junco (noun)	Junco hyemalis (noun)
common North American junco having grey plumage and eyes with dark brown irises	common North American junco having grey plumage and eyes with dark brown irises