Gyrfalcon
Photo
by Douglas Herr
Falco rusticolus
AKA: Greenland falcon, Asiatic gyrfalcon
SIZE: 19-25 inches
WINGSPAN: 43-54 inches
FLIGHT SPEED:
FEEDING HABITS: Eats mostly birds, with ptarmigans being the primary target. Will eat some small mammals.
IDENTIFICATION: The gyrfalcon has three color phases.
In general they are slightly larger than the peregrine with slower
wingbeats and will fly closer to the ground.
- The white phase, which is sometimes called silver
phase, has white underwings with dark tips, and the white underbody
can have some spotting, but not always. The back and upperwings are
barred and spotted with dark markings. The juveniles of this phase
have underparts that are completely streaked and bluish eyerings and
ceres. The adult has a yellow cere.
- The gray phase grey upperparts with lighter colored
baring. The underparts are pale with bars and spots. Feet and cere
are bright yellow. From below, the gray and dark phase gyrfalcons
will show darker wing linings than flight feathers. Cere is slate
blue on juvenile. Juvenile also shows more streaking on the
underparts, instead of spots, and will show a faint mustache mark.
- The dark phase has similar markings to the gray but
with dark slate gray or brown upperparts. Intergrades exist between
gray and dark phases.
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