harpy eagle vs Harpia harpyja

harpy eagle and Harpia harpyja both are nouns.

Word	Noun	Adjective	Verb	Adverb
harpy eagle	Yes	No	No	No
Harpia harpyja	Yes	No	No	No

As nouns, harpy eagle and Harpia harpyja are synonyms defined as:

harpy eagle and Harpia harpyja: large black-and-white crested eagle of tropical America

Other synonyms of harpy eagle include harpy.

harpy eagle (noun)	Harpia harpyja (noun)
large black-and-white crested eagle of tropical America	large black-and-white crested eagle of tropical America