Egretta caerulea vs little blue heron

Egretta caerulea and little blue heron both are nouns.

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

As nouns, Egretta caerulea and little blue heron are synonyms defined as:

Egretta caerulea and little blue heron: small bluish-grey heron of the western hemisphere

Egretta caerulea (noun)	little blue heron (noun)
small bluish-grey heron of the western hemisphere	small bluish-grey heron of the western hemisphere