whooper swan vs Cygnus cygnus

whooper swan and Cygnus cygnus both are nouns.

Word	Noun	Adjective	Verb	Adverb
whooper swan	Yes	No	No	No
Cygnus cygnus	Yes	No	No	No

As nouns, whooper swan and Cygnus cygnus are synonyms defined as:

whooper swan and Cygnus cygnus: common Old World swan noted for its whooping call

Other synonyms of whooper swan include whooper.

whooper swan (noun)	Cygnus cygnus (noun)
common Old World swan noted for its whooping call	common Old World swan noted for its whooping call