passenger pigeon vs Ectopistes migratorius

passenger pigeon and Ectopistes migratorius both are nouns.

Word	Noun	Adjective	Verb	Adverb
passenger pigeon	Yes	No	No	No
Ectopistes migratorius	Yes	No	No	No

As nouns, passenger pigeon and Ectopistes migratorius are synonyms defined as:

passenger pigeon and Ectopistes migratorius: gregarious North American migratory pigeon now extinct

passenger pigeon (noun)	Ectopistes migratorius (noun)
gregarious North American migratory pigeon now extinct	gregarious North American migratory pigeon now extinct