Hi -
Lars has raised some very good points. First, he wrote, "I feel the Cassiar is
a hybrid swarm, not a real subspecies, and one should expect broad
variability." One of the characteristics of a hybrid swarm is variability in
the traits differing between (or among) the parental taxa. If you have a clear
or simple view of what a member of a hybrid swarm "should" look like, then you
are missing the point.
In my opinion, the currently accepted dogma on the relationships between Junco
taxa are oversimplified. American bird taxonomists tend to see speciation
following one model or process: geographic isolation followed by gradual
divergence in isolation, etc. This model seems to do a good job of explaining
species relations in most North American birds, but there are a handful of
groups where "special circumstances" enable speciation to occur much faster,
and sometimes without isolation. "Special circumstances"might include unusual
combinations of migratory behavior and courtship dynamics, strong disruptive
selection on morphology, and "anomalies" in the groups respective genomes.
IMO, these groups include northern geese (Anser and Branta), prairie grouse,
large gulls, the owl groups Otus/Megascops and Glaucidium, Empidonax
flycatchers, Vireos, Titmice, Gnatcatchers, Juncos, Crossbills, possibly other
Fringillid finches, and probably a few others.
If I remember correctly,a paper was published several years ago reporting that
the different "subspecies" of Junco differed in chromosomal structure. This
takes me back over 40 years to my college genetics courses, where we studied
chromosomal rearrangements in fruit flies. The first implication (to my
knowledge not yet examined in Juncos) is that chromosomal inversions and
translocations often interfere with meiosis when cross-bred, and so can (but
not always) become reproductive isolating mechanisms. If this happened to be
the case with some of the junco taxa, then species limits might need to be
revisited.
Lars also pointed out some aspects of the photographed junco - particularly
pink on flanks - that I think are out of the normal range of Slate-colored
Junco plumage.
Wayne
On 3/27/2019 9:25:57 PM, Lars Norgren <larspernorgren@xxxxxxxxx> wrote:
One of the most striking photos l've ever seen on line was an intergrade
flicker, frontalview, one half of the tail feathers yellow, the other side of
the tail dark orange. I suppose it could have been photoshopped, but assuming
it was real, why couldn't the same happen with Juncos? Will someone tell me, do
eastcoast Juncos regularly have pinkish-buff at the tail end of their flanks?
On Wed, Mar 27, 2019, 5:23 PM Hendrik Herlyn <hhactitis@xxxxxxxxx
[mailto:hhactitis@xxxxxxxxx]> wrote:
I've had a very similar bird at our place in Corvallis in the past few days
that I've been wondering about. The funny thing about my bird is that its two
sides look slightly different from each other. On the right side, the gray head
and chest end in a somewhat concave pattern, and the gray bleeds along the
flanks, with some rufous tinges mixed in toward the rear. On the left side, the
gray head and chest from more of a hooded look, with gray flanks. So one side
resembles a classic Slate-colored (except, perhaps, for the rufous tones in the
flank), while the other side looks more like Cassiar's - very strange!
Unfortunately, the bird has refused to pose for pictures thus far.
Regarding Bob's bird, I agree with Lars and Dave that it still falls within the
Slate-colored spectrum (to the extent that I'm familiar with it).
Cheers
Hendrik
On Wed, Mar 27, 2019 at 5:06 PM David Irons <llsdirons@xxxxxxx
[mailto:llsdirons@xxxxxxx]> wrote:
I would call this an immature Slate-colored for the issues Lars raises.
Dave Irons
Beaverton, OR
Sent from my iPhone
On Mar 27, 2019, at 5:00 PM, Lars Norgren <larspernorgren@xxxxxxxxx
[mailto:larspernorgren@xxxxxxxxx]> wrote:
Some portion of the cognoscenti will discount this as a Cassiar because it
lacks an Oregon style hood, black clearly delineated from grey flanks, a convex
margin at the upper breast. Also the bright red back...? I have examined well
under a hundred Slate-coloreds in half a century. Others on this list have
looked at thousands. Are the pinkish-buffy flanks OK for S-c. A similar bird
was put up here earlier this year with the same slate colored foreflank but
buff at the rear, the same brown back and nape. Some said it was well within
the range of regular S-c J. I feel the Cassiar is a hybrid swarm, not a real
subspecies, and one should expect broad variability. Lars
On Wed, Mar 27, 2019, 2:44 PM Robert O'Brien <baro@xxxxxxx
[mailto:baro@xxxxxxx]> wrote:
My wife just spotted this bird at our feeder. Not a birder, she's always asking
me "What's that bird?", often a song sparrow; but
she hit the jackpot this time. And just in time as these winter birds/migrants
are due to leave before long. I'm not sure I've ever had one here before, at
least that I recognized. And over many years we've had almost yearly
Slate-colored, one or two that returned for a successive year. Recently there
was a OBOL post of a immature female Slate-colored, so I'm not totally sure of
this one. So?
An interesting "subspecies" or is this just a hybridizing contact zone? And if
not a hybrid between 'Oregon' and 'Slate-colored',
what would such a hybrid look like relative to Cassair?
For more on the enigma of the Cassair, see eBird comments at
https://ebird.org/pnw/news/dark-eyed-junco-races-oregon-slate-colored-and-cassiar/
[https://ebird.org/pnw/news/dark-eyed-junco-races-oregon-slate-colored-and-cassiar/]
Bob OBrien
Carver OR
--
__________________________
Hendrik G. Herlyn
Corvallis, OR
"Nature is not a place to visit. It is home."
-- Gary Snyder
