Greetings all,
After looking at the various photos of this bird, I tend to agree with
Hendrik's take. The amount of pattern in the face and the streaking on the back
are both problematic for what normally qualifies as "Slate-colored." I think
that the bird falls into the altivagans pile, whatever that actually is
genetically. I've never been able to grasp why birds presenting as altivagans
are included in the Slate-colored group, as there are many aspects that align
much better with the Red group, most notably the more russet and not dusky
chocolatey brown color of the spotting below, the streaking on the mantle (only
shows up in Reds) and the mix of russet and gray in the face pattern, also a
Red characteristic. I strongly suspect that altigvagans is like cismontanus in
Dark-eyed Junco...an intergrade (likely Red X Sooty) rather than a truly
legitimate subspecies.
All this said, I struggle with the idea of slotting this bird in the
Slate-colored group for two reasons. First, it creates the notion that
Slate-colored is likely to occur in Oregon (particularly western Oregon) during
the winter months. In my experience this is not the case. Secondly, I think it
misrepresents what a bona fide Slate-colored Fox Sparrow might look like. In my
opinion, endorsing birds that look like this one as a Slate-colored Fox
Sparrows, particularly west of the Cascades during winter, does a disservice to
observers who may be trying to work out the differences between the various
subspecies groups of Fox Sparrows that do occur in Oregon at various times of
the year. As it is, there is general uncertainty about the respective ranges of
Slate-colored vs. Thick-billed, including the question of whether their
breeding ranges overlap. Further, there is plenty of confusion about how to
tell Slate-coloreds and Thick-billeds apart visually. Plus, there are some
observers are challenged to tell Sooty and Slate-colored apart. Calling a bird
a Slate-colored when it looks mostly unlike the actual Slate-coloreds that
breed in and migrate through eastern Oregon just adds to the confusion.
I wish I had an easy answer to this problem, as there is surely interest in
designating these birds in a way that calls out the fact that they are out of
the ordinary. I just don't think endorsing them as Slate-coloreds is the
solution.
Dave Irons
________________________________
From: orebird-bounce@xxxxxxxxxxxxx <orebird-bounce@xxxxxxxxxxxxx> on behalf of
Hendrik Herlyn <hhactitis@xxxxxxxxx>
Sent: Sunday, February 14, 2021 3:36 AM
To: OReBird <orebird@xxxxxxxxxxxxx>
Subject: [orebird] Re: Portland Fox Sparrow -- good for "Slate-colored"?
Hi all,
I would feel pretty comfortable accepting this bird as a member of the
schistacea group, provided that we consider altivagans to be part of that
group. To me, this looks somewhat intermediate between a "pure" Slate-colored
and an altivagans, given the amount of brownish spotting on the flanks (more
typical for altivagans, which tend more toward a rufous underside than
schistacea), but I don't have enough experience with these taxa to be certain
one way or another. But I think we can safely eliminate Red, Sooty, and
Thick-billed forms.
Just my 2 cents.
Hendrik
On Sat, Feb 13, 2021 at 5:36 PM Jay Withgott
<withgott@xxxxxxxxxxx<mailto:withgott@xxxxxxxxxxx>> wrote:
Hi all —
OK, I’ve been sitting on this one for a while and it’s past time to deal with
it. Below are photos in 3 checklists of a Fox Sparrow at Mount Tabor in
Portland that is thought to be perhaps a “Slate-colored” (schistacea) or
perhaps “altivagans” (which I think w/b within eBird’s “schistacea group”).
* Here’s the initial checklist by finder Ross Barnes-Rickett:
https://ebird.org/checklist/S79291975
* Here are photos by Tom McNamara: https://ebird.org/checklist/S79619591
* Chris Hinkle has seen the bird 3 times and lists it as Slate-colored:
https://ebird.org/checklist/S80666664
The crown color appears possibly a bit different to me in Ross’s vs. Tom’s
photos, but everyone seems to feel this is the same bird.
eBird has 4 options for Fox Sparrows (which may not be enough to encompass the
actual variation, of course, esp. re: whatever “altivagans” is). The 4 options
are:
* Sooty (unalaschcensis group)
* Thick-billed (megarhyncha group)
* Slate-colored (schistacea group)
* Red (iliaca/zaboria)
I’m thinking the Portland bird should probably be confirmed as Slate-colored
(schistacea group), but what would you all do with this bird?
Thank you!
Jay
--
__________________________
Hendrik G. Herlyn
Corvallis, OR
"Nature is not a place to visit. It is home."
-- Gary Snyder
