Subject: [Tweeters] Glaucous Gull or. . . ?
Date: Wed Feb 12 09:39:26 PST 2020
From: Robert O'Brien - baro at pdx.edu

Adult Glaucous Gulls are rare in the Pacific NW in winter but Iceland gulls
with white-tipped primaries are extremely rare.
Highly unlikely to be Iceland Gull And in flight, the Iceland Gulls have
only white-tipped primaries, not entirely white primarie as Glaucous have.
This could be hard to distinguish unless in flight. I will separately
forward to Tweeters an email I sent recently to OBOL, the Oregon Lists
Server.regarding
Iceland Gulls.
Bob OBrien Portland

On Wed, Feb 12, 2020 at 5:04 AM Tim Brennan <tsbrennan at hotmail.com> wrote:


> Hey Tweets,

>

> I posted a Glaucous Gull sighting on the 10th from the mouth of the Cedar

> River, but am pulling that identification. At the time, the only confusion

> species I considered was a hybrid Glaucous x Glaucous-winged, and the pale

> iris made that easy to rule out. Looking on eBird, the sightings of adult

> Glaucous Gulls were pretty infrequent, so I was poking around looking for

> anything else, and came across this:

>

> https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551

>

> <https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551>

> Glaucous Gull Similar Species to, All About Birds, Cornell Lab of

> Ornithology

> <https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551>

> Similar looking birds to Glaucous Gull: Glaucous-winged Gull Nonbreeding

> adult, Glaucous-winged Gull First winter, Iceland Gull Adult (Iceland),

> Iceland Gull Nonbreeding adult (Thayer's), Iceland Gull First winter

> (Iceland), Herring Gull Nonbreeding adult (American)

> www.allaboutbirds.org

>

> Iceland Gull (Iceland) was not something I had considered at the time, and

> is an even more disastrous ID (insomuch as there aren't any sightings of

> these guys in the state). That said I can speak to the 3 or 4 features that

> would help with the ID. I am running off of this image, and any other

> crumbs I could find off of the Internet, and about 10-15 minutes of scope

> views of the gull at 150-200 feet in excellent lighting.

>

> Mantle: I was looking at how pale the mantle was, in trying to rule out

> Glaucous x Glaucous-winged. My Sibley's said that the mantle would be

> slightly darker in a hybrid than in a pure Glaucous Gull, and my thought

> was "How can what I'm looking at be darker than anything?" It wasn't white,

> but such a pale pale grey. The images show the lighter mantle of the

> Iceland (Iceland) almost melting into the white around it, and that fit the

> impression I got from the bird. The Internet gave me a range for Glaucous

> Gull - usually slightly darker, and usually a better delineation of the

> mantle, but not always.

>

> Bill: Those bills both have the red spot I noted. I did not note the color

> in the sighting, but the Glaucous appears to have a pretty heavy bill that

> tends a little towards school bus orange/yellow. This wasn't true of all of

> the images I found for the species (color wise), but my impression overall

> was that the bill seemed fairly "normal" and also has me leaning towards

> Iceland (Iceland).

>

> Facial expression: The sum of the iris, head shape, orbital - seems to add

> up to a friendlier expression on Iceland (Iceland), something that seems

> helpful when sorting Thayer's and Herring. This bird did not seem angry.

>

> Size: Would have helped . . . but it was in the water, and was not

> something I was looking for.

>

> I hope it shows up again, and someone gets a picture. Gulls are, for me, a

> mess. There are so many hybrids running around, and subtle differences to

> sort one out from the other. They are usually more frustrating than

> enjoyable. Look closely at a gull. . . ? Why would I do that, and ruin a

> perfectly fine day of birding?? But this one was striking, whatever it was.

> With any luck, someone more pay-attentiocal than I will have a go at IDing

> it, although there were a few eBird lists from the mouth yesterday that

> didn't turn it up.

>

> Cheers,

>

> Tim Brennan

> Renton

> _______________________________________________

> Tweeters mailing list

> Tweeters at u.washington.edu

> http://mailman11.u.washington.edu/mailman/listinfo/tweeters

>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman11.u.washington.edu/pipermail/tweeters/attachments/20200212/bc00d4f2/attachment.html>