glaucous-winged gull at Teller 5, Boulder

[William H Kaempfer]

John Vanderpoel and I observed a first cycle Glaucous-winged Gull this morning at Teller Lake #5 in Boulder (off Valmont near 95^th St.) 

 

Teller 5 is excellent for gulls right now and worth a visit (even if that %@#$ Golden-crowned Sparrow can’t be found).  The lake dried out this past fall leaving a harvest of dead fish, mainly huge catfish, I think, in the frozen mud toward the east end of the reservoir.  This attracts a group of about 100 gulls during the day. There are two noteworthy things about this collection of gulls.  First since they are feeding on dead fish the flock is mainly large, pink-legged gulls.  I would say that only 25% are Ring-billed Gulls which is unheard of in Colorado for a group of 100+ gulls.  Second, because they are feeding, one can get quite close to them (within 100 yards) and have excellent views.  This group has had multiple Thayer’s plus Lesser Black-backed, Great Black-backed and now Glaucous-winged in the past week.  Interestingly, all of these good birds have been first (or second) cycle.

 

Here is my (probably lame) description of the Glaucous-winged from eBird: Large first cycle gull. Overall larger than nearby 1st cycle Thayer's. Uniform pale tan overall with wingtips not differentiated from overall color of the bird. Large all black bill.

 

Bill Kaempfer

Boulder

[Christian Nunes]

Birders,

Bill's post reminded me about an experience I had this past weekend when I went to study the gulls at Teller #5. As I drove up, I could see a large concentration of birds on the lake bed eating the dead fish (grass carp, I think. Probably some catfish, too). But as soon as I started to walk out towards the lake from the parking lot, gulls started flying overhead. When I reached the lake, much to my chagrin, there was a local birdwatcher (name known but withheld!) who was walking out on the flats, sans scope, and clearly flushing the gulls. The gulls didn't stick around for seconds, but just flew off towards Valmont where they are definitely not easy to study. Poor form, not only for bothering the birds, but for ruining the experience for the many other birders who enjoy the spectacle, especially on a beautiful weekend day. 

This behavior I expect from errant dogs and children, but not birders. To enjoy the gulls, do everyone a favor and bring a scope! And since I'm directly involved with managing wildlife at N. Teller #5, I'd like to remind people to please stay on the trails! Humans on a trail are predictable, and thus animals can habituate to a certain amount of disturbance. Hiking out on the lake bed to get a better view without appropriate optics or to get better photos is clearly inappropriate. There's a trail on the south and east side of the lake, affording plenty of observation opportunities in a variety of light conditions. What made matters worse was that this birder didn't stop when the birds began to get nervous. He kept walking closer causing 90% of the birds to fly away, and the other 10% had ceased their foraging and were walking away nervously. At that point I walked away myself, in a funk that even a few good birds could barely brighten. 

Bird responsibly,

Christian Nunes

Boulder, CO

paja...@hotmail.com

http://www.flickr.com/photos/christian_nunes/

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From: William....@Colorado.EDU
To: cob...@googlegroups.com
Date: Thu, 24 Jan 2013 15:53:26 -0700
Subject: [cobirds] glaucous-winged gull at Teller 5, Boulder

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[Paul Hurtado]

Assuming it is the same bird, I can't help but wonder if the bird shown in the photos here isn't a Glaucous-winged X Glaucous hybrid? 

   http://ebird.org/ebird/view/checklist?subID=S12716613

Overall it looks pretty pale, has some pink showing through on the basal 2/3 of the bill, and has fairly well marked upper parts, i.e., the mantle and upperwing feathers look like they're showing a lot of pale with darker internal markings, very reminiscent of Glaucous Gull. 

Thoughts?

Paul Hurtado
Columbus, OH (& Pueblo, CO)

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Paul J. Hurtado
Postdoctoral Fellow, The Ohio State University
Mathematical Biosciences Institute, http://mbi.osu.edu/
Aquatic Ecology Laboratory, http://ael.osu.edu/

E-mail: hurta...@mbi.osu.edu
Webpage: http://people.mbi.ohio-state.edu/hurtado.10

[Bryan Guarente]

I believe I saw this same bird this afternoon.  I will disagree with Paul and David about this bird, but only because I can't identify it as either of their possibilities.  The bird David Dowell photographed is very light like the one I saw.  There isn't another gull for good size comparison, but the bird I saw this afternoon was SMALLER than the 3rd cycle Herring Gull near it.  Now, it is possible that the bird I saw was different than the one David saw, so please keep that in mind.  Because of that, I will describe the bird I saw.

My description: I found this bird because of its *exceptionally* pale primaries.  It was facing away initially, so I didn't get much of a look at the head and back.  Light dull pink legs, lighter than Herrings around.  My initial look without knowing the size made me think Iceland Gull because it was so light (especially in the primaries), but that was squelched after I saw the bird in profile and the head was more Herring-like than Thayer's/Iceland.  Beak was black as viewed with binoculars, but with a scope, the beak was definitely slightly pink at the base seemingly more so on the mandible than the maxilla and extending ever so slightly down the beak toward the tip.  Beak seemed longer than Herring without much of a gonydeal angle from what I could tell, but I don't give that much credence from my views.  I didn't get the impression that David had of the large chest of the bird.  The bird seemed more Thayer's-shaped in the body than Herring or larger-gull shaped.  The patterning on the bird's body was much lighter and finer than on any of the other first cycle birds around.  I never got a good look at the open tail.

I mentioned that I disagreed with both Paul and David.  I only disagree because of the size comparison I had.  If it were either a Glaucous-winged or the hybrid Paul suggested, it should still be bigger or the same size as a Herring Gull, not smaller.  I can't place this bird yet, but am open to suggestions.  Currently I am recording "medium to large gull sp."  Does someone want to help school me in this gull?

Bill Kaempfer or John Vanderpoel, is this the same bird you were seeing that you called a Glaucous-winged Gull?

If you missed it, here are the photos:
http://ebird.org/ebird/view/checklist?subID=S12716613

 

Bryan Guarente
Instructional Designer
The COMET Program
University Corporation for Atmospheric Research
Boulder, CO

---

From: Paul Hurtado <paul.j....@gmail.com>
To: CObirds <cob...@googlegroups.com>
Sent: Friday, January 25, 2013 2:23 PM
Subject: Re: [cobirds] glaucous-winged gull at Teller 5, Boulder

Webpage: http://people.mbi.ohio-state.edu/hurtado.10 --

[Alex Brown]

Late this morning (Friday Jan 25)  I observed a (the?) first winter Glaucous-winged Gull at Teller Lake #5, located near Valmont Rd/N 95th St in
Boulder County.  My view of the bird suggested a darker coloration than shown in the ebird photo link included in Paul Hurtado's comment.
I am not sure whether this a question of different lighting conditions or a color saturation issue with the photos. The photos seem to show a far more "bleached-looking" bird than my scope views suggested.

The bird in question had a very uniform pale brown overall plumage color. When it spread its wings the plumage all the way from the
neck, down through the mantle and all along the tail was an identical color. The spread wings were also uniform looking with nothing
obviously dark or different along the wing. When standing and viewed from the side the folded primaries looked a slight bit darker but this
may have just been a sunlight/shadowing effect. The bill was all dark and appropriately large --- much larger than on the nearby Thayer's
Gulls. The legs seemed darker than the photos show but still pinkish (rather than black). The bird appeared identical in size to first
winter Herring Gulls with both standing side by side.

The variety among the gulls at Teller #5 is unusual for Boulder County allowing excellent views of different species side by side.
There were many Herring Gulls (first winters, adults, and maybe a 3rd year), one adult California Gull, several first winter Thayer's
Gull and one 2nd year, and close to 100 Ring-billeds. No sign of anything "Black-backed" though. The turnover in birds was significant
with new gulls coming in continuously.

Alex Brown
Boulder