golden-crested kinglet vs Regulus regulus

golden-crested kinglet and Regulus regulus both are nouns.

Word	Noun	Adjective	Verb	Adverb
golden-crested kinglet	Yes	No	No	No
Regulus regulus	Yes	No	No	No

As nouns, golden-crested kinglet and Regulus regulus are synonyms defined as:

golden-crested kinglet and Regulus regulus: European kinglet with a black-bordered yellow crown patch

Other synonyms of golden-crested kinglet include goldcrest.

golden-crested kinglet (noun)	Regulus regulus (noun)
European kinglet with a black-bordered yellow crown patch	European kinglet with a black-bordered yellow crown patch