western kingbird vs Arkansas kingbird

western kingbird and Arkansas kingbird both are nouns.

Word	Noun	Adjective	Verb	Adverb
western kingbird	Yes	No	No	No
Arkansas kingbird	Yes	No	No	No

As nouns, western kingbird and Arkansas kingbird are synonyms defined as:

western kingbird and Arkansas kingbird: a kingbird seen in western United States; head and back are pale grey and the breast is yellowish and the tail is black

western kingbird (noun)	Arkansas kingbird (noun)
a kingbird seen in western United States; head and back are pale grey and the breast is yellowish and the tail is black	a kingbird seen in western United States; head and back are pale grey and the breast is yellowish and the tail is black