nightingale vs Luscinia megarhynchos

nightingale and Luscinia megarhynchos both are nouns.

Word	Noun	Adjective	Verb	Adverb
nightingale	Yes	No	No	No
Luscinia megarhynchos	Yes	No	No	No

As nouns, nightingale and Luscinia megarhynchos are synonyms defined as:

nightingale and Luscinia megarhynchos: European songbird noted for its melodious nocturnal song

nightingale (noun)	Luscinia megarhynchos (noun)
European songbird noted for its melodious nocturnal song	European songbird noted for its melodious nocturnal song