tree swallow vs Hirundo nigricans

tree swallow and Hirundo nigricans both are nouns.

Word	Noun	Adjective	Verb	Adverb
tree swallow	Yes	No	No	No
Hirundo nigricans	Yes	No	No	No

As nouns, tree swallow and Hirundo nigricans are synonyms defined as:

tree swallow and Hirundo nigricans: of Australia and Polynesia; nests in tree cavities

Other synonyms of tree swallow include tree martin.

tree swallow (noun)	Hirundo nigricans (noun)
of Australia and Polynesia; nests in tree cavities	of Australia and Polynesia; nests in tree cavities
bluish-green-and-white North American swallow; nests in tree cavities