Florida gallinule vs marsh hen

Florida gallinule and marsh hen both are nouns.

Word	Noun	Adjective	Verb	Adverb
Florida gallinule	Yes	No	No	No
marsh hen	Yes	No	No	No

As nouns, marsh hen is a hypernym of Florida gallinule; that is, marsh hen is a word with a broader meaning than Florida gallinule:

Florida gallinule: North American dark bluish-grey gallinule
marsh hen: any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens

Other hypernyms of Florida gallinule include gallinule, swamphen, water hen.

Florida gallinule (noun)	marsh hen (noun)
North American dark bluish-grey gallinule	any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens
	a coot found in North America