Cassiar or Slate-coloured Junco? Another round!

[paulos]

So it's time to open back up everyone's favourite bird ID question.

There has been a male cassiar junco around for several days, matching all the points I would look for (Oregon-like dark hood, grey sides, greyer back than Oregons). There was also a slate-coloured around a few days ago. Then today something more confusing showed up. It has a brownish tinge to the back, a dark hood, but a bit lighter than most of the Oregon males. Its hood sort of bleeds into the side. While they are two distinct tones, the side seems darker than I would think it should for a cassiar. However, it doesn't quite fit the normal Slate-coloured category to me; for a slate-coloured male there would usually not be a distinct line between the hood and the sides, or the hood and the back. I think it could still be a slate-coloured, but I'm looking for input. Any ideas?


Cassiar or Slate-coloured Junco? by Paul Foth, on Flickr


Cassiar or Slate-coloured Junco? by Paul Foth, on Flickr


Cassiar or Slate-coloured Junco? by Paul Foth, on Flickr


Cassiar or Slate-coloured Junco? by Paul Foth, on Flickr


Cassiar or Slate-coloured Junco? by Paul Foth, on Flickr

[Gord]

Ugh these guys are tough. I'll take the easy/lame way out and say hybrid

[Deleted]

Ha, this one again. It's one of the most challenging ID issues we run into, but I personally find it enlightening to try to understand some of the issues it raises. That's one of the ways we learn, isn't it? It has certainly pushed me to dig deeper and learn quite a lot (I hope).

I started, as usual, with SIbley's illustration, but I more or less by accident looked at the useful Wikipedia article on Dark-eyed Junco, and read through a lot of the long (very long) and complicated (very complicated) comments in the "Juncos: What do we know?" thread on ID Frontiers in January 2004 that's linked under External Links down at the very bottom of the long Wiki article. It's a discussion by some of the top ID experts and raises lots of issues (more questions than answers, of course!), like which definition of species some prefer, how many species are there in the junco groups across the US and Canada and how does the Cassiar form fit in, as well as opinions and interchanges and replies among those experts on what marks actually distinguish Cassiar Junco from other Juncos. I'm deliberately being vague about terms like species, subspecies, hybrids, etc., because it appears the situation with these juncos is not nearly as clear as most of us probably have assumed, including me.

To summarize some of the discussion:
Cassiar Junco breeds in a relatively small area of northern BC and a bit of Alberta, where the ranges of Oregon and Slate-colored Juncos intersect (though they tend to spread out widely in small numbers both to the east and to the west during the winter, as we would expect.)
Females juncos tend to spread more widely than males do, making ID more tricky of course, since we will expect to see more female Cassiars (which can be indistinguishable from Oregon females) than males.
Incidentally, in at least two places in the thread mentioned, contributors say they think Sibley's illustrations are good for Cassiar Junco, which I find reassuring and it simplifies things.

*IF "hybrid" can be used loosely for crosses between species or subspecies, then Cassiar Junco MAY be a hybrid between the coastal "Oregon" Juncos we normally see here (actually a group of half a dozen similar subspecies spread along mostly the west coast) and the widespread northern and eastern "Slate-colored Junco" (actually a group of at least 2 similar subspecies).
*IF rather, "hybrid" should be used only in the case of crosses between species, and "intergrade" should be used of crosses between subspecies (think Northern Flicker, for example), then Cassiar Junco MAY be an intergrade between the Oregon and Slate-colored subspecies (though technically both Oregon and Slate-colored are each a group of several subspecies) of Dark-eyed Junco. That's assuming that the current designation of Dark-eyed Junco as a single species including 5 separate groups (one is the Oregon group, and another the Slate-colored group) is valid. There's significant disagreement over this. Nor is there agreement that Yellow-eyed Junco, which you will only see in the mountains of southern Arizona unless you go to Mexico, is a separate species from some of the subspecies of Dark-eyed Junco. It's complicated!
And:
*IF Cassiar Junco doesn't represent a stable population, then it's most likely a hybrid or intergrade (depending on the above) between Oregon and Slate-colored and is not a true subspecies.
*IF on the other hand, Cassiar Junco is a stable population no longer needing parentage from Oregon and Slate-colored to keep it viable, then it is probably a subspecies (rather than a hybrid or intergrade) and only then should it be given a distinct trinomial scientific name (Junco hyemalis cismontanus). It would then presumably be considered the third species placed in the Slate-colored group. Of course, it may well be in transition so maybe both are true, as some experts suggest.
In either case, Cassiar Juncos should in plumage appear intermediate between Oregon and Slate-colored.

Now to get to more practical information on ID:
As I see things, the main differences in plumage between MALE (a) Slate-colored vs (b) Oregon Juncos are:
1. (a) very little or no brown tinge on back vs (b) a noticeable brown tinge mixed with the gray on the back, or back may even show more brown than gray (can be variable in both species),
2. (a) gray band all along side below folded wing, lighter gray than wings and back vs (b) brownish band along side,
3. (a) little or no noticeable contrast in colour between hood and back vs (b) noticeable contrast (can be variable in both species),
Oregon certainly show more distinct contrast, but you don't have to google too many photos of Slate-colored to find some that do show a contrast, and also some that show some brownish tinge on the back.
4. (a) concave shape to bottom of dark hood/bib along breast vs (b) convex [drooping] shape to bottom of hood/bib along breast.

I note that Sibley's illustration of the "Canadian Rocky Mountains" form (Cassiar) shows 1(a), 2(a), 3(b) and 4(b), so two characteristics of each presumed parent species.
I also note from my experience, that 1 particularly, and also 3 tend to vary along a range, while 4 particularly, and also 2 seem to show up as either/or.
Therefore I take 2a and 4b to be the most distinctive distinguishing plumage marks for Cassiar - Rounded, drooping bib like Oregon, with gray side stripe like Slate-colored.
This seems to match with some of the remarks in the ID thread, that in hybridization or intergradation, some plumage characteristics seem to carry over as either/or and some seem to show up anywhere along a continuum or range. I take the latter variable ones to be less useful for ID and those that appear as distinctly one or the other to be more useful. My own quick rule of thumb is to check through the Oregon Juncos for one that looks like an Oregon but has distinct gray all along the sides instead of brown. Or look for a Slate-colored that has the distinct drooping bib of an Oregon.

I don't think it's a coincidence that in most cases where we debate the ID of supposed Cassiar Juncos we struggle with the amount of brown showing in the back or with the amount of contrast between the hood and the back -- these two I think are the most variable in Oregon and Slate-colored to start with, and are perhaps not the best markers. Intermediate shapes of the bottom line of the hood/bib seem to very seldom show up, and I haven't seen enough Cassiar juncos to say if there is much variation in the side stripes.

So I would hazard a guess that Paul's photo shows either a Slate-colored Junco with maybe more brown than usual and more hood contrast than usual, or a variant Cassiar Junco with very unusual Slate-colored bib shape. Based on what I've said above, variant Cassiar would appear to be less likely.

Of course, to further complicate things, there is also the possibility that it's a backcross (if Cassiar is an intergrade) or an intergrade (if Cassiar is a subspecies) between a Cassiar Junco and an Oregon Junco, which is probably something like what Gord is suggesting.

But I am far from certain about much of this and I welcome any feedback or correction if anyone has waded through all this!

[Gord]

Stan, a very detailed and well thought out response that is highly educational. Thanks very much. I will be referring back to it for sure as I read more and look at the juncos still at my feeder before the last of them disperse for higher elevations or further inland.

[paulos]

Wow. Thank you Stan! That is very helpful, especially your comments about the variety in the brown back and back/hood contrast.

[KevinC]

Hopefully it's okay to post some pics of a Junco I came across near Hope Airport on April 5th?

Any thoughts on what type this is?
Just a Slate-coloured with lots of contrast?

If there is any brown, it is just the very slightest tinge, and the cap is very distinct - although I get that these characteristics are variable. The sides do look grey to me, but I haven't figured out the concave/convex bib shape.

Thx
Kevin

I'm not sure how to get these pics to show, but the links are below:

Pic 1
Pic 2
Pic 3

[paulos]

This looks very much like a more classic Cassiar junco.

[Deleted]

I would agree with Paulos. The bird in Kevin's photos is what I expect a male Cassiar junco to look like. Compare it with the illustration in Sibley of what he labels Canadian Rocky Mountains (form). The photos show maybe a bit lighter gray on the sides than expected, but still gray rather than brown. If the bird in the photo had brown sides instead of gray, and had some brown on the back, it would look like a standard Oregon.

To visualize the hood/bib shape, think of wearing a T-shirt, and pulling it part way up your upper body -- level in a line all across your chest and curving back around your sides. This is like the concave line around the bottom of the hood/bib on a Slate-colored Junco. Then think of a baby wearing a bib that hangs down, rounded at the bottom and not extending back around the sides. This is like the convex hood/bib shape on an Oregon. Does this help?

It seems from what I've read that Cassiar should consistently show the baby bib shape, like Oregon, rather than the line across, like Slate-colored (though in most other characteristice it resembles Slate-colored more than Oregon). This to me is a major thing to look for. The first thing that jumps out at me when I see a Slate-colored is this different hood shape, along with the more uniform gray in general.

[KevinC]

Thank you both! I am just re-learning how to bird and am quickly finding out how much I have to learn! I do not have much in the way of books - the only book I have with western species is so old that it still calls a kestrel a sparrowhawk - but I will have a look at the big Sibley book at the Heron Reserve when I am there again on Sunday.
I think I get the bib idea now, thanks to your tips, Stan.
As I write this, there are a couple of Oregons just a few feet away, letting me look at their bibs.