Carolina parakeet vs parakeet

Carolina parakeet and parakeet both are nouns.

Word	Noun	Adjective	Verb	Adverb
Carolina parakeet	Yes	No	No	No
parakeet	Yes	No	No	No

As nouns, parakeet is a hypernym of Carolina parakeet; that is, parakeet is a word with a broader meaning than Carolina parakeet:

Carolina parakeet: extinct parakeet whose range extended far into the United States
parakeet: any of numerous small slender long-tailed parrots

Other hypernyms of Carolina parakeet include paraquet, paroquet, parrakeet, parroket, parroquet.

Carolina parakeet (noun)	parakeet (noun)
extinct parakeet whose range extended far into the United States	any of numerous small slender long-tailed parrots