Great comments so far...one of the many things I love about Tweeters.

Gyrs are circumpolar and so they do exhibit a wide range and continuous
gradation of plumage coloration from almost pure white to pure black
depending on the location. For example, Greenland is famous for its high
number of white gyrs. In fact, expeditions were sent there from Europe in
the middle ages specifically for that reason. White gyrs were highly sought
after then and still are now.

I think what Wayne was trying to point out (and forgive me if I am
mis-interpreting you Wayne), is that here on the wet side of the Pacific
Northwest (Fraser, Lummi and Skagit Flats), most of the brown birds that we
see (and many that I have banded over the years) are exclusively first year
or juvenile falcons. Such individuals will usually have a beautiful pale
blue or grayish cere and orbital ring and often whitish feet instead of the
the typical adult yellow or gold. Several banded juvenile gyrs have returned
here in subsequent years and they have all molted into the gray coloration
that to me is the "standard" plumage in this sub-region.

I have never been lucky enough to see a white bird here on the west side of
the mountains but one was shot on the Skagit back in the 1950's so they can
get here. At the other end of the spectrum, I once saw an extremely
beautiful pure black Gyrfalcon on the Samish Flats, but only once and never
again. It was an unforgettable bird.

To complicate matters, some birds have also shown up with a pure white front
and a silver gray back and these are usually called "silver" gyrs by the
locals.

Great comment by Hal too. I remember in the early years of hawk ID (1960's),
we all called these birds "light phase" or "dark phase" but I also remember
Bill Clark later adopting the word "morph" instead of "phase" specifically
to counteract the idea that these birds were moving through a plumage
seasonally as Eric has pointed out. "Morph" seems to have stuck among most
of the hawk watchers that I associate with here in NA.

I do want to add one more thing. I have commented on it here before. There
is a really odd type of contour plumage "di-chromaticism" that occurs among
our local Gyrfalcons. As a result, it can be really difficult, especially
for beginners, to accurately call a bird brown or gray. I think that this is
especially true here in the dark, gray, overcast winter conditions of the
NW. I know that it seems like it should be easy but oftentimes it is not. I
vividly remember releasing a banded brown bird on Sunset Road on Samish and
as we all watched her fly away, she appeared to transform from a known brown
bird into a gray gyr before our eyes. Several people saw this and commented
on it. The color seemed to change with distance. It was really odd.

Finally, there are some other gyr experts living up in Whatcom County such
as Paul De Bruyn and Randy Knapp that might want to comment here. Both of
these guys have much experience with local gyrs.

Bud Anderson
Falcon Research Group
Box 248
Bow, WA 98232
(360) 757-1911
falconresearch at gmail.com
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