Regulus regulus vs golden-crested kinglet

Regulus regulus and golden-crested kinglet both are nouns.

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

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

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

Other synonyms of Regulus regulus include goldcrest.

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