Pagophila eburnea vs seagull

Pagophila eburnea and seagull both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pagophila eburnea	Yes	No	No	No
seagull	Yes	No	No	No

As nouns, seagull is a hypernym of Pagophila eburnea; that is, seagull is a word with a broader meaning than Pagophila eburnea:

Pagophila eburnea: white Arctic gull; migrates as far south as England and New Brunswick
seagull: mostly white aquatic bird having long pointed wings and short legs

Other hypernyms of Pagophila eburnea include gull, sea gull.

Pagophila eburnea (noun)	seagull (noun)
white Arctic gull; migrates as far south as England and New Brunswick	mostly white aquatic bird having long pointed wings and short legs