gerfalcon vs Falco rusticolus

gerfalcon and Falco rusticolus both are nouns.

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

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

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

Other synonyms of gerfalcon include gyrfalcon.

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