American robin vs Turdus migratorius

American robin and Turdus migratorius both are nouns.

Word	Noun	Adjective	Verb	Adverb
American robin	Yes	No	No	No
Turdus migratorius	Yes	No	No	No

As nouns, American robin and Turdus migratorius are synonyms defined as:

American robin and Turdus migratorius: large American thrush having a rust-red breast and abdomen

Other synonyms of American robin include robin.

American robin (noun)	Turdus migratorius (noun)
large American thrush having a rust-red breast and abdomen	large American thrush having a rust-red breast and abdomen