Sitka Nature

(click to see slightly larger version)

I took this picture last February at Swan Lake. Currently, my best guess is that this is a hybrid gull, possibly Glaucous-winged x American Herring Gull, or a somewhat odd (to my eyes) Thayer’s Gull.

I eliminate pure Glaucous-winged Gull because of the very dark on the primaries. I eliminate pure Herring Gull due to the dark eyes and not-black on the primaries.

(click for slightly larger version)

I’m not sure that I can really eliminate Thayer’s Gull, though neither am I convinced it is a Thayer’s Gull. This may be due primarily to my inadequate understanding of the range of variation in Thayer’s Gulls, however. The orbital ring of this bird seems to be almost a mix of yellow and pink, suggesting the possibility of a hybrid, as Thayer’s Gulls should have a pink to pinkish-purple orbital ring. This bird also seems to be a little bit bulky for a Thayer’s Gull, though unfortunately I neglected to take a picture that included other, more easily identified, gulls for comparison. There is a skirt, which Thayer’s Gulls can show, but it’s more typical of Glaucous-winged Gulls. Also, the dark on the wing-tips seems a bit light for most Thayer’s Gulls. If there are other characters I am neglecting to consider that would help with the identification of this gull, I would be interested in learning about them.

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I saw this gull the same day as the one considered above. It also seems to suggest the possibility of a hybrid Glaucous-winged x American Herring Gull. Though it looks more or less like a third-cycle Glaucous-winged Gull, the eye is unusually pale, and the wingtips are a bit dark for a pure Glaucous-winged Gull.

More Gull ID challenges

This afternoon I was able to observe the mystery warbler again several times, and was also able to get some better photos. In addition, I discovered there was a second warbler, this one far more yellow than the first. Though the warblers did not remain together in an exceptionally close association, they did seem to move around with each other to a certain extent. Both were actively foraging, mostly in the open grassy or weedy areas, but occasionally (and briefly) on trees. It’s possible that they utilized trees more than I realized, because they were most easily observed on the ground. On a few occasions, I saw them come up with pretty good sized insect larva that I took to be caterpillars. When they got one, they would usually fly up to a branch to eat it (or perhaps I only noticed it when they did this).

Comments I received on the first post, as well as through e-mail, mostly suggested Orange Crowned-warbler, though I did have one response that it might be a Palm Warbler if it did a lot of tail pumping. As I did not notice any significant tail pumping, it probably was not a Palm Warbler, though the earlier photos showed some similarity to a Palm Warbler photographed in Gustavus recently. While the second warbler seems a bit more typical of an Orange-crowned Warbler, I’m still not absolutely convinced of the identity of the first warbler. However, it seems most likely that it’s also an Orange-crowned Warbler perhaps of the Taiga race (Vermivora celata celata), rather than the more typically seen (in Sitka) Pacific race (V. c. lutescens). The yellow rump still seems a bit strange, but otherwise things seem to fit.

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Eating a caterpillar(?)
Still showing a yellow rump
Apparent pale supercilium in earlier photo seems to have been an artifact
Faint pale yellow wash on breast, contrasts against pale gray of throat and head.
Caught another caterpillar(?)

The second warbler, presumed to be an Oranged-crowned Warbler. I belive it’s a new late record for this species in Sitka.

Additional photos can be found at:
24 November Photos: Backyard Birds

Update: I was able to get additional photos this afternoon. I have added them, plus additional comments, in a second post.

Yesterday my son told me he saw an Orange-crowned Warbler (well, I think it was some other color crown, but he still has a little trouble keeping all the names he is learning straight) outside his window. He said it flew around to the side of the house, so I went out to take a look and got a very brief glimpse at a bird that was clearly a warbler. I did not get a good enough look at it to identify it, but it did not look that far off from an Orange-crowned Warbler. I told him to keep an eye out for it, and we saw it very briefly, but I did not see enough to make me think it wasn’t an Orange-crowned Warbler. This morning he told me that it was outside again, so I went outside to take a look.

It seems to be hanging around in a loose association with the neighborhood junco flock. The first thing I noticed about its appearance was how grey it seemed. Much moreso than I associate with Orange-crowned Warblers I have seen around here before. I was able to get a few pictures (of marginal quality) in the dim light, and I hope they’re enough to get an identification, but so far I’m stumped.

(Click on photos to see larger version)
Yellow rump
Broken eye-ring and perhaps a pale supercilium
Undertail coverts appear pale yellowish
Overall grayish tone is different than I’ve seen before
No white edging to coverts

No streaking on breast
Again very pale gray is different than I’ve seen before

I’m assuming this is a first year bird, but it still looks different than the Orange-crowned, Yellow-rumped, and Yellow Warblers I’ve seen around here before.

The lack of streaking and yellow rump seems to rule out Orange-crowned Warbler, both Pacific and Taiga.

First winter Tenessee Warblers appear to be much yellower overall but without a yellow rump.

Virginia’s Warblers (never reported in Alaska, so very unlikely based on geography) seems to be ruled out by the broken eye-ring and pale supercilium.

Nashville warbler seems ruled out by broken eye-ring, pale supercilium, and lack of pale on throat and breast.

Yellow Warbler seems ruled aout by yellow-rump, lack of pale edges on tertials, and broken eye-ring.

Yellow-rumped Warbler seems ruled out by lack of white edges on coverts, pale supercilium, yellowish undertail coverts, and grayish (rather than brownish) coloring.

Palm Warbler seems to have stronger (and longer) pale supercilium, some streaking, a more brownish color, and white corners to its tail (which I did not see when this bird flew).

Those are the closest I could come up with, but they all seem to be problematic for one reason or another. Hopefully I will see this bird again and be able to get some better pictures of it, but that remains to be seen.

I have had a few responses to the Loon Identification post I made a couple of days ago. One of them pointed out that there is a discussion of Loons in the Peterson Field Guide to Advanced Birding by Kenn Kaufman. I have had the book for some time, but did not think to look in it, so that was helpful. I also appreciate the other responses I have had, as the discussion helped clarify for me the difficulties I am having. I now think that all but one of the birds I am having trouble with are all Common Loons (perhaps all first winter, but I’m not sure). The other bird is hard to be certain about due to the poor quality of the photo, but I’m leaning toward Red-necked Loon due to the relatively small bill and the general lack of pattern on its neck.

Below is one photo of each of the other loons in question. I have arranged them from the most Pacific Loon-like to the least Pacific Loon-like, to my eyes. (Numberings are from the previous post, look there to see additional photos of some of these loons.)

(Click thumbnails for larger versions.)

(Bird #1)
(Bird #5 and #6; there were two at the time, but I’m not sure I photographed both)
(Bird #2)
(Bird #3)
(Bird #4)
(Bird #8)

It seems to me that the first five pictures above show something of a continuum of patterning on the neck. However, it also seems like lighting, posture, and positioning play a significant role in the apparent patterning (or lack thereof) on the neck. To me, the sixth bird looks signficantly different than the first five, but it’s worth noting that it’s also the only one without its head/neck extended up rather then folded down a bit.

It’s also worth noting the following picture of Bird #4, which look far more Common Loon-like.

Upon realizing that I had misplaced the third picture of Bird #4 (the one that’s in the list above) and it actually belonged with these two, I came to think that probably all of the birds were Common Loons since the third picture fit into the continuum of birds that looked a little unusual for Common Loons and had elements suggestive of Pacific Loons, but also, in different postures, looked very much like a Common Loon.

Of course, I could be wrong about all of this, but I like to think I’m on the right track. Hopefully someone will set me straight, if I’m not.

Questions that remain for me are:

How variable is the neck pattern in Common Loons? Does the first bird, which seems to have no neck pattern at all, but otherwise looks very much like the other birds, fit within this variation?

How variable is the amount of white around the eye in Common and Pacific Loons? Pictures I have of birds that are clearly Pacific Loons (scroll to bottom for photos) seem to show white around the eye, though the field guides I’ve looked at suggest there is not any. The birds pictured above do not have as much white as other birds I have taken pictures of that are clearly Common Loons (scroll to bottom for photos), and less than the field guides I’ve looked at seem to suggest they should have.

Is it unusual for a Common Loon to show a chin strap, as Bird #8 seems to?