GYRFALCON
gyrfalcon, gerfalcon, Falco rusticolus
(noun) large and rare Arctic falcon having white and dark color phases
Source: WordNet® 3.1
Etymology
Noun
gyrfalcon (plural gyrfalcons)
(obsolete) Any large falcon, especially as used to fly at herons.
Falco rusticolus, a large bird of prey that breeds on Arctic coasts and islands of North America, Europe and Asia.
Source: Wiktionary
Gyr"fal`con, n. Etym: [OE. gerfaucon, OF. gerfaucon, LL. gyrofalco,
perh. fr. L. gyrus circle + falco falcon, and named from its circling
flight; or cf. E. gier-eagle. See Gyre, n., Falcon.] (Zoöl.)
Definition: One of several species and varieties of large Arctic falcons,
esp. Falco rusticolus and the white species F. Islandicus, both of
which are circumpolar. The black and the gray are varieties of the
former. See Illust. of Accipiter. [Written also gerfalcon,
gierfalcon, and jerfalcon.]
Source: Webster’s Unabridged Dictionary 1913 Edition