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zdgesb84

Junco Subspecies

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Not a pure State-colored. Either Cassiar Junco (J.h.cismontanus) or Oregon group. This is a really tough ID, especially because we don't know what Cassiar Junco is. Theories are either an obscure subspecies, or intergrades between SC and Oregon.

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3 minutes ago, zdgesb84 said:

Thanks.  Is protocol to list on eBird as the Oregon sub-species or just lumping it together as Dark-eyed?

I would put it under Oregon subspecies with a note that it's likely this subspecies or Cassiar. That way a reviewer will get back to you and hopefully make a determination as to which one it is, if possible. 

I think it looks okay for Oregon personally, but hopefully a reviewer who has more experience can sort it out. 

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Definitely appears to be an Oregon. Male Cassiar's typically have grey sides similar to a Slate-colored, but with a clear darker hood. I believe female Cassiar's have marginal dark brown sides (versus extensive, somewhat orange-pink sides like this), and are probably usually best left as "female Slate-colored / Cassiar" since they're pretty hard to distinguish from regular Slate-colored (or, confusingly, Slate-colored x Oregon).

Here's a decent write-up on Cassiar juncos: https://ebird.org/pnw/news/dark-eyed-junco-races-oregon-slate-colored-and-cassiar/

Edited by tedsandyman
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On 11/26/2018 at 5:23 PM, tedsandyman said:

Definitely appears to be an Oregon. Male Cassiar's typically have grey sides similar to a Slate-colored, but with a clear darker hood. I believe female Cassiar's have marginal dark brown sides (versus extensive, somewhat orange-pink sides like this), and are probably usually best left as "female Slate-colored / Cassiar" since they're pretty hard to distinguish from regular Slate-colored (or, confusingly, Slate-colored x Oregon).

...

Well, as akiley said, "Cassiar" may be a name for "Slate-colored x Oregon".

I agree that I wouldn't hesitate to call that an Oregon.

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I made that distinction because from what I've read, Cassiar juncos seem most often to be considered birds from an area ("central Yukon south through northern BC and into central Alberta", according to this article) where Slate-colored x Oregon's have hybridized for a long period of time, creating a more distinct stable subspecies; whereas a Slate-colored x Oregon would be a full Oregon hybridizing with a full Slate-colored (which may or may not look the same as a Cassiar). I believe this theory originated with Harry Swarth way back in 1920, when he said they were,

Quote

"good subspecies," in the sense that the birds over a certain area ... exhibit a combination of characters distinguishing them from other described forms, and they remain true to these peculiarities within . . . close limits. (Swarth 1922)

Later, notable junco expert Alden H. Miller agreed, saying

Quote

[Cassiar juncos are a] group of hybrid origin [i.e. Slate-colored x Oregon], now stabilized, which occupies a geographic area in the breeding season to the exclusion of other forms. (Miller 1941)

In case you haven't gotten enough about the subject, here's a fairly current (2013) article about Cassiar's (where I got those quotes from).

Edited by tedsandyman
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9 hours ago, tedsandyman said:

I made that distinction because from what I've read, Cassiar juncos seem most often to be considered birds from an area ("central Yukon south through northern BC and into central Alberta", according to this article) where Slate-colored x Oregon's have hybridized for a long period of time, creating a more distinct stable subspecies; whereas a Slate-colored x Oregon would be a full Oregon hybridizing with a full Slate-colored (which may or may not look the same as a Cassiar). I believe this theory originated with Harry Swarth way back in 1920, when he said they were,

Later, notable junco expert Alden H. Miller agreed, saying

In case you haven't gotten enough about the subject, here's a fairly current (2013) article about Cassiar's (where I got those quotes from).

I see your point.  If all the males breeding in that area look pretty much like standard Cassiars, whereas Slate-colored x Oregon males elsewhere may look like that or have some other combination of characters, it makes sense to call Cassiar a distinct subspecies, and that seems to be what Swarth said.

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Yeah, that's about it.. The other factor is that it's supposed (on what basis, I'm not sure, though we do have 100 or so years of evidence now) that Cassiar juncos have bred in that area for a long period, so you have many generations of hybrid birds breeding (with presumably some full Oregon or Slate-colored's breeding there), which makes the characteristics of the birds more predictable. In comparison, many "first generation" hybrid birds (for example, ducks or geese) can look wildly different than other birds with the same parentage. 

From personal observation, I have seen some juncos that seemed to have the traits of a Slate-colored and Oregon (for example, a clear hood with gray sides), but not falling into what are the "accepted" characteristics of a Cassiar.

I think the topic of juncos hybrids is quite interesting , since they are a very good example (one of the best in North America) of the processes of speciation (how new species are created).

Edited by tedsandyman
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Thinking about it more, this bird could possibly be an Oregon (OR) with some Pink-sided (PS) parentage, as the sides look quite extensive for an OR (compare with this eBird report https://ebird.org/view/checklist/S33547687).

At risk of laboring a topic that may not be entirely relevant to this site, I'd also like to clarify that I use the term hybrid in the last post in a loose sense (covering crosses of species and subspecies), since that seems to weather changes of taxonomic status better than 'intergrade', though at this time that may be more accurate to describe them. The exact line separating species from subspecies is tenuous (and controversial), and, at least to the bird checklist authorities, largely hinges on frequency of interbreeding where the birds' range overlap. On that basis it's interesting to note that, at least according to the eBird Range Map, that OR juncos (exclusive of PS) and Gray-headed's (GH) range appear to overlap in summer in a few places (for example, around Salt Lake), but only 5 reports of OR x GH have ever been accepted to eBird; comparatively, there are many more (50+) reported PS x GHs.

That somewhat raises the question (in my mind anyway) if OR and GH readily interbreed enough to be considered conspecific, though other factors probably account for the dearth of recorded birds: e.g. the comparative amount that OR & GH's range overlap versus PS & GH's (i.e. more for the latter); the ease with which OR x GH can be distinguished and / or how well-known OR x GH is known among the birder community (in contrast I know that there is at least one published article aimed at birders for identifying PS x GH juncos).

Admittedly I'm an amateur ornithologist so I'm not sure the exact point authorities feel compelled to separate or conflate species, though I imagine some more extensive surveys of hybrid juncos where subspecies overlap in breeding would help clear things up (and / or DNA analysis).

Edited by tedsandyman

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A final note I should have mentioned is species vs. subspecies are also separated based on how readily the hybrid birds are successful in breeding with one of their parents' species / subspecies (backcrossing). Not sure what the taxonomists do if birds don't interbreed very frequently where they overlap, but  the hybrids still successfully backcross...

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