Limnodromus griseus vs grayback

Limnodromus griseus and grayback both are nouns.

Word	Noun	Adjective	Verb	Adverb
Limnodromus griseus	Yes	No	No	No
grayback	Yes	No	No	No

As nouns, Limnodromus griseus and grayback are synonyms defined as:

Other synonyms of Limnodromus griseus include greyback.

Limnodromus griseus (noun)	grayback (noun)
a dowitcher with a grey back	a dowitcher with a grey back
	a sandpiper that breeds in the Arctic and winters in the Southern Hemisphere