water turkey vs darter

water turkey and darter both are nouns.

Word	Noun	Adjective	Verb	Adverb
water turkey	Yes	No	No	No
darter	Yes	No	No	No

As nouns, darter is a hypernym of water turkey; that is, darter is a word with a broader meaning than water turkey:

water turkey: blackish New World snakebird of swampy regions
darter: fish-eating bird of warm inland waters having a long flexible neck and slender sharp-pointed bill

Other hypernyms of water turkey include anhinga, snakebird.

water turkey (noun)	darter (noun)
blackish New World snakebird of swampy regions	a person or other animal that moves abruptly and rapidly
	fish-eating bird of warm inland waters having a long flexible neck and slender sharp-pointed bill