Jerry wrote:

>Since there has been some question as to which Rosy Finch (Hepburn's or
>Pribilof) we have seen, I thought I would go public with the Photos.:-)
>These photos were taken last year, at Lake Lenore, (south of Grand
>Coulee) with my 30 old camera, and are not very good.
>
>Three people whom I consider VERY good birders said that the birds in
>the photo looked like the Pribilof form. The ones we saw yesterday
>looked the same as the ones in the photo. That is why it was stated that
>they were the Pribilof form in the previous post titled 2nd Annual Trip.
>
>If interested go to the second photo at:
>
>http://homepage.usr.com/c/composites/48071.shtml
>
>Is they is, or is they ain't the Pribilof form?



Jerry and Tweeters:

Rosy-Finches are the major species group I study, so I took a look at the
photo Jerry posted, and they AIN'T the Pribilof form, they are Hepburn's
(ie. subspecies littoralis).

But let's back up a bit. There are three subspecies that have gray cheeks,

(1) littoralis (Hepburn's) which breeds in the Cascades from approx. Mt.
McKinley (Denali), Alaska south to Mt. Shasta, California, and is the
predominant wintering form in Washington state. [A non-gray-cheeked
subspecies, tephrocotis, which breeds in the Canadian Rockies southward as
far as the Bob Marshall Wilderness in Montana, is the other form we get in
Wash.]

(2) griseonucha, which breeds on Kodiak Island, the Alaskan Peninsula and
the Aleutian Islands and their Russian counterpart, the Commander Ids
(=Komandorskie Ids). In winter there is some movement between islands and
perhaps some movement westward toward the Alaskan Peninsula and coastal
southeast Alaska, but the vast majority (probably well over 99%) remain
within their breeding range in winter. Most workers on this subspecies have
considered them nonmigratory. Of course strays are possible, but there are
no published records south of Alaska.

(3) umbrina, which breeds on the Pribilof Islands. Many remain year-round,
but some apparently migrate, in at least some years, to the Aleutian
Islands. There are no published winter records south of the Aleutians.

The latter two forms (i.e. griseonucha and umbrina) are what are sometimes
collectively called the Pribilof form or the Aleutian form. They both
differ from littoralis (Hepburn's form) in being much darker in body color,
much bigger (body weight twice that of littoralis; they are a BIG finch),
having less gray under the chin, and a proportionately longer, more slender
bill than littoralis (or than any other mainland subspecies; but this
trait, though very diagnostic, is hard to see except in the hand).

Now, returning to the birds in the photo. While the photo isn't as sharp as
one would prefer for this purpose, I judge that they are littoralis because
of the following:

(a) The gray appears to go broadly down the cheek and then BROADLY UNDER
THE CHIN, for those in the picture at the right angle to view this trait.
This is never true for griseonucha or umbrina, whereas it is often true for
Hepburn's.

(b) The body color is much too light for the Pribilof form. Those in the
photo look dark because most of their bodies are in shadow, but note the
backs that are in sunlight. They are golden brown. I have watched and
handled hundreds of griseonucha on the Aleutians where I've studied them,
and I've examined every museum specimen of them in collections on this
continent, and none of them could ever look as light as the backs of these
birds, regardless of the time of day and lighting. You might look at the
photo of the "Aleutian" Rosy-Finch on page 325 in my account of the
Rosy-Finches in the The Audubon Society Master Guide to Birding, volume 3.
If you do so, don't let the great difference in bill color between
Rosy-Finches in the various photos fool you. Those with yellow bills are
winter birds, those with black are summer, breeding birds. There is no
difference in bill color between the various species and subspecies of
Rosy-Finch. For a photo of littoralis that is in pretty good color
register, see the color plate on page 302 of The Audubon Society
Encyclopedia of North American Birds by John K. Terres. On the other hand,
the illustrations in Peterson's Western Birds and in the National
Geographic guide show no difference between the two in body and chin color,
and are wrong in those regards.

Lastly, I might return to the point made earlier that the Pribilof form(s)
are not long distance migrants and there are no published records south of
Alaska, so their presence here is very unlikely. But, unlikely and never
are not the same thing. Birds do get around, so one can't say with
certainty that there won't be a first time.


Richard (Dick) E. Johnson
Curator, Conner Muesum
Washington State University
Pullman, WA 99164-4236