Cassin's kingbird vs Tyrannus vociferans

Cassin's kingbird and Tyrannus vociferans both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cassin's kingbird	Yes	No	No	No
Tyrannus vociferans	Yes	No	No	No

As nouns, Cassin's kingbird and Tyrannus vociferans are synonyms defined as:

Cassin's kingbird and Tyrannus vociferans: a kingbird seen in the southwestern United States; largely grey with a yellow abdomen

Cassin's kingbird (noun)	Tyrannus vociferans (noun)
a kingbird seen in the southwestern United States; largely grey with a yellow abdomen	a kingbird seen in the southwestern United States; largely grey with a yellow abdomen