rusty blackbird vs blackbird

rusty blackbird and blackbird both are nouns.

Word	Noun	Adjective	Verb	Adverb
rusty blackbird	Yes	No	No	No
blackbird	Yes	No	No	No

As nouns, blackbird is a hypernym of rusty blackbird; that is, blackbird is a word with a broader meaning than rusty blackbird:

rusty blackbird: North American blackbird whose bluish-black plumage is rusty-edged in the fall
blackbird: any bird of the family Icteridae whose male is black or predominantly black

Other hypernyms of rusty blackbird include New World blackbird.

rusty blackbird (noun)	blackbird (noun)
North American blackbird whose bluish-black plumage is rusty-edged in the fall	any bird of the family Icteridae whose male is black or predominantly black
	common black European thrush