possible Pacific Loon on Valmont Reservoir, Boulder

[Jeff Parks]

Hi all -

Last month, there was a Pacific Loon reported on Baseline Reservoir just outside of Boulder, which is one of my regular haunts.  I hustled out there, and managed to spot a Loon, but couldn't tell for sure if it was  Pacific or Common Loon.  It appeared to have the white 'necklace', which I associate with a Common Loon.  Several of the people reporting it are pretty well-versed in the birding world, including Ted Floyd, so I thought I must have missed it.  There were a couple of loons there for the next week or so, but I couldn't get a good enough look to make a definitive call for a PALO (not that I am an expert by any means). 

This afternoon I headed over to the Valmont Reservoir Complex, since a lot of the other ponds around here are drying up, and I knew that there would be something interesting on Valmont.  I started at the Open Space Office on Cherryvale and hiked up to the top of the little mesa in the middle of the three reservoirs.  While looking around on Valmont Reservoir, I spotted a loon, close enough to get a pretty good look, and with decent light.  I dialed the scope up, hoping to see some details that would tell me whether it was a Common or Pacific Loon.  At first, I thought that it was a Common, since I was seeing a larger spot of white under the chin, but it didn't have the jagged look that a Common Loon has.  After watching it for about 20 minutes, I am thinking that it was a Pacific Loon, since in some of the views I got the white didn't appear to extend beyond the side of the head, and the forehead rises more gently than a Common Loon, as far as I can tell.  I tried to get some pictures, but I guess I need another system for taking pictures through the scope so I don't jiggle it so much.  I am attaching a couple, but the quality is not very good.  This bird looks similar to the one that I saw on Baseline last month.

As for other birds, there was a big flock (120 +) of Red-Breasted Mergansers, a couple of Eared Grebes (also on the near side of the water for good looks through the scope),  and a couple of Meadowlarks in the trees, with some Robins and Flickers ...

good birding -

Jeff Parks
Boulder CO

[Jeff Parks]

Sorry, didn't mean to confuse anyone, I started at the Open Space Office on 75th, about halfway between Arapahoe and Valmont.  It won't be long and I will be drooling on myself ...

JP

[Jeff Parks]

OK, after some feedback from people that know a lot more than I do, this bird is most likely a Common Loon.  The primary indicator is the line on the neck which separates the white on the front and the darker color on the back of the neck.  There is a white 'bubble' near the top of the neck that extends to the back which breaks up the smooth line along the side of the neck.  Although it is not a jagged triangular shape, the overall profile is not a smooth line when viewed from the side.  It is not real clear in my pictures, but can be seen to some extent.  In addition, in the upper picture, the bill looks pretty long, and this matches my observation notes.  As far as I can tell, the bill on a PALO is shorter and not quite as thick as the bill on a COLO.  While it is hard to tell from these photos, I noted during observation that the bill looked larger, in line with a COLO. 

Reasons why I thought it might be a PALO were the head profile seemed to be more rounded with a gentler slope to the forehead, although I did get a shot where the head looked flatter on the top.  The neck pattern (white/dark border) at times looked smoother, but there was the obvious white 'bubble' extending towards the back visible at times.
 
After looking at all of the details, this one looks to be a Common Loon, although with some variation in the neck color pattern.  I did find a couple of pictures online that look similar to this one, identified as COLO.

It was a good day to be outside, none the less.

cheers -

Jeff Parks
Boulder CO