swan vs whooper swan

swan and whooper swan both are nouns.

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

As nouns, whooper swan is a hyponym of swan; that is, whooper swan is a word with a more specific, narrower meaning than swan:

swan: stately heavy-bodied aquatic bird with very long neck and usually white plumage as adult
whooper swan: common Old World swan noted for its whooping call

swan (noun)	whooper swan (noun)
stately heavy-bodied aquatic bird with very long neck and usually white plumage as adult	common Old World swan noted for its whooping call

swan (verb)	whooper swan (verb)
to declare or affirm solemnly and formally as true
move about aimlessly or without any destination, often in search of food or employment
sweep majestically