Loon Identification

It’s the time of year that loons are most easily observed around Sitka, and I was recently reminded that I have pictures of several different loons taken over the last three years that I have had a hard time figuring out. I’ve got my best guesses for most/all of them, but for each there is some question that remains. I suspect most of the difficulty I’m having is due to variation in characters (both between individuals, and within the same individual due to difference in posture) that I do not have a good handle on. I imagine some (all?) of them are fairly straightforward to someone with more loon experience, so I’m hoping I might be able to get a little help from birders with more knowledge. I would appreciate any comments on identifications and/or the range of variation in the character traits that are causing me trouble.

Loon comparison
Update: For an idea of the trouble I’ve had, these two photos were taken about a year apart. I have tended to think of the first (Bird #1) as a Pacific Loon and the second (Bird #5 or #6) as a Common Loon. Until today, I have never thought to compare them. Now I see these are close enough that they could almost be the same bird. Certainly it seems like whatever I think one is, the other must be also. I think this analysis also applies to Bird #2 and Bird #3, as well. It seems that if I can get an identification for this form that keeps showing up, I would have the most of the problem birds I see figured out (the other ones are more problematic due to distance/poor conditions for photography).

(Click on any thumbnail below to see a larger version of image)

Pacific(?) Loon (Bird #1)
This loon was the first I ever took pictures of, back on 14 December 2004. I have changed my mind about whether it was a Pacific Loon or not several times over the time since, though most often I have considered it a Pacific Loon. What inclines me toward Pacific Loon is that it seems to have the clean line between white and gray on the neck and it’s not as bulky as I tend to think of Common Loons being. On the other hand, the bill seems more bulky than I would expect for a Pacific Loon, it seems to have white around the eye, and there’s no hint of a chinstrap. However, it looks even less like a Common Loon.

Common(?) Loon (Bird #2)
Snowy weather does not lend itself to optimal photographic conditions, and this photo reflects that. However, I hope the bird can be seen well enough for identification purposes. My best guess is that this is a Common Loon, but I am troubled by the apparent lack of white partial collar and the seemingly short/small bill. On the other hand, the line between white and gray on the neck does not seem as clean as it should be for a Pacific Loon, and the bill seems a bit more robust than I would expect on a Pacific Loon. This bird was observed in early November 2006.

Common(?) Loon (Bird #3)
This may be the same bird as the previous one, though this picture was taken 16 January 2007. The bill seems more reminiscent of a Common Loon, though it does not seem to have the bulk I expect of a Common Loon. To my eyes it does not appear to have a partial white collar, nor does it have much white around the eye (as would be expected with a Common Loon). While bulk/size and lack of white around the eye seems consistent with Pacific Loon, the bill does not, nor does the contrast/line between light and dark on the neck.

Common(?) Loon (Bird #4)
This loon, photographed in the south corner of Crescent Harbor 12 December 2005, seemed to me a Common Loon. I still lean pretty hard toward Common Loon, as it’s got the bulk and the contrast/line between the light and dark of the neck seems more consistent with a Common Loon. On the other hand, the bill seems a little short and there is no white above the eye (as would be expected on a Common Loon). Update: Looking at the third picture, it’s apparent there is some white above the eye. I had forgotten the third photo was of this bird (rather than the ones taken the same day outside the harbor) until going back through the pictures and double checking my original notes on it.

Common(?) Loons (Bird #5 and #6)
These are pictures of two birds that seemed to be swimming together near Crescent Harbor breakwater on 12 December 2005. I think they are the same species. I’m leaning toward Common Loons as they have some white around the eye and the bill seems fairly bulky. However, they seem a little less bulky than I would expect (compare with the bird above, though maybe things like the apparent thickness of neck have more to do with posture than anything else). Also there seems to be a hint of a chinstrap and there does not appear to be a partial white collar (though it’s still not as clean a line between light and dark as I might expect on a Pacific Loon).

Update: Now that I have compared one of these photos with one I am thinking of as a Pacific Loon (see above), I’m a little more inclined to think these are Pacific Loons.

Pacific(?) Loon (Bird #7)
I only saw this loon briefly from a distance while I was kayaking in late October 2006. My current thinking is that it’s a Pacific Loon, but I also wonder about Red-throated Loon. I’m not sure that I can rule it out. Given the poor quality of this photo, perhaps there cannot be a definitive answer, but I figure it’s worth a try.

Common(?) Loon (Bird #8)
Seems to have the bulk of a Common Loon. The bill looks a little short, there’s a chinstrap, white edging to feathers on its back seems unusual, and I don’t really see a white collar. Seen 27 October 2006.

About matt goff

I am an aspiring naturalist who seeks to learn all that I can about the more-than-human aspects of this place that is my home.
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