Falco rusticolus vs gerfalcon

Falco rusticolus and gerfalcon both are nouns.

Word	Noun	Adjective	Verb	Adverb
Falco rusticolus	Yes	No	No	No
gerfalcon	Yes	No	No	No

As nouns, Falco rusticolus and gerfalcon are synonyms defined as:

Falco rusticolus and gerfalcon: large and rare Arctic falcon having white and dark color phases

Other synonyms of Falco rusticolus include gyrfalcon.

Falco rusticolus (noun)	gerfalcon (noun)
large and rare Arctic falcon having white and dark color phases	large and rare Arctic falcon having white and dark color phases