Egretta caerulea vs heron

Egretta caerulea and heron both are nouns.

Word	Noun	Adjective	Verb	Adverb
Egretta caerulea	Yes	No	No	No
heron	Yes	No	No	No

As nouns, heron is a hypernym of Egretta caerulea; that is, heron is a word with a broader meaning than Egretta caerulea:

Egretta caerulea: small bluish-grey heron of the western hemisphere
heron: grey or white wading bird with long neck and long legs and (usually) long bill

Egretta caerulea (noun)	heron (noun)
small bluish-grey heron of the western hemisphere	grey or white wading bird with long neck and long legs and (usually) long bill