junco vs Junco hyemalis

junco and Junco hyemalis both are nouns.

Word	Noun	Adjective	Verb	Adverb
junco	Yes	No	No	No
Junco hyemalis	Yes	No	No	No

As nouns, Junco hyemalis is a hyponym of junco; that is, Junco hyemalis is a word with a more specific, narrower meaning than junco:

junco: small North American finch seen chiefly in winter
Junco hyemalis: common North American junco having grey plumage and eyes with dark brown irises

Other hyponyms of junco include dark-eyed junco, slate-colored junco.

junco (noun)	Junco hyemalis (noun)
small North American finch seen chiefly in winter	common North American junco having grey plumage and eyes with dark brown irises