Two rare gulls at White Rock -- Little & Thayer's

[betsy]

The Little Gull is still around and can almost always be found flying off the point that's just north of the old paddleboat houses (where they now keep the sculls) in late afternoon -- say around 5:00 p.m. For anyone who hasn't yet seen it, it's even smaller than the Bonaparte's, is a bit grayer on top, and has decidedly dark underwings with a touch of trailing white. It flies buoyantly, like the Bony's, and likes to be in their company. You might first see it when it's about about eight or ten feet above the water and then you can follow it as it dips down to the water's surface.

The excitement today is a first winter Thayer's Gull (on the spillway in early morning) that Chris Runk says has been there for a couple of days (but he wasn't entirely certain it was a Thayer's and not a 1st winter Herring Gull until he spent two hours watching a gull video last night to get the salient clues to look for). Bob Stone took photos of it this morning and when he sends them to me I'll post them.

Meanwhile, here's a web page with a comparison of these two young gull species (as well as their adult versions -- slide down the page for the first winters).

http://montereybay.com/creagrus/MTYlistTHGU.html

And another good page on a first winter Thayer's Gull that appeared in Denmark:

http://www.surfbirds.com/mb/Features/thayers-gull.html

Martin Reid's index of Thayer's Gull photos on his website:

http://www.martinreid.com/Gull%20website/thguinx.html

[Ben Lamb]

Hi Betsy -

Despite a couple of attempts earlier in the season I still haven't managed to see the Little Gull. Where exactly is the point where it is being seen? Any particular strategy for picking it out?

Thanks

[Perry]

I would suggest using the West Lawther drive all the way south to the white colored structures. Park there and walk out to the point. Have a seat and start checking every Bony you see. Afternoon is better as you will not be looking into the sun. If you go in the morning, then use East Lawther and look the other direction.

[betsy]

Ben, if you want to see the point in question on the map of White Rock Lake, I finally figured out how to make the map appear full size. Look at my post that has the map in the Forecasts forum for White Rock. When you get the expanded version of the map, slide down to the bottom of the page -- it's the point north of the dam, with the words TeePee Hill and Paddle Boat Lot in the water around it. The entrance to the paddle boat parking lot is just north of an old RR bridge.

In the late afternoon a mixed flock of Ring-billed and Bonaparte's Gulls tends to fly around over the lake off of that point. Earlier, most of them are apt to be sitting on the surface of the water, which makes it pretty hard to find the Little Gull, but around 5:00 p.m. (which will be 6:00 p.m. as of tomorrow, I think) you're pretty likely to be able to find it flying, and then you can scan all the Bonaparte's Gulls, as Perry said, looking for the one that's a little bit smaller and has very dark underwings. Took me about a half hour to find it the first time, and only a few minutes to find it the second time. It will probably be a trifle to the right of the point as you're standing or sitting there (near the Tee Pee Hill words is a good place to park yourself, or on the bench at that area).

[betsy]

OK, here are Bob Stone's photos of the "supposed Thayer's Gull" as he put it. So, what do you think? Is it a first winter Thayer's in your mind? (Good gull exercise!) Click on the thumbnails to open them in separate windows.

[Ben Lamb]

At WRL this morning we found the gull in question very quickly, sitting off by itself and eating a fish. My wife Beth got some pictures, which we'll attempt to paste in below. This evening we're going to try for the Little Gull, so I hope we get lucky again.

http://farm1.static.flickr.com/164/417980433_b2ed98c36c_o.jpg

http://farm1.static.flickr.com/150/417980430_8387be09b3_o.jpg

http://farm1.static.flickr.com/163/417980428_89418f2ec6_o.jpg

[betsy]

Thanks mucho for these, Ben and Beth. The second and third are particularly helpful in giving us views we didn't have before. I've been reading up on "The Thayer's Gull Complex" in Kenn Kaufman's Advanced Birding and he says it's crucial to see certain characteristics of the wing pattern in flight [although raised wings do equally well for the feathers we can see that way] to confirm a first winter Thayer's Gull id:

1. "The outer several primaries have the narrow, outer webs darker brown than the rest of the wing. This darker color extends onto the inner webs only at the tip of each feather. The rest of the broad inner web of each primary is distinctly pale (whitish)." We can see that very clearly in your second photo.

2. "The secondaries are similarly colored, with the outer webs dark and the inner ones entirely pale. Taken together, the pattern of the secondaries (as viewed from above) is one of a broad and distinct, but broken, dark bar across the trailing edge of the wing." I can just barely make out the broken aspect of the dark secondary bar in the flight shot, I think, but because the wings are stretched out so much more on the raised wing photo than they'd be in flight, I can even see the dark/light web colors of individual secondary feathers on the underside of the near wing, which would normally be concealed in flight.

Kaufmann also mentions that the dark tips of the primaries show up as a dark trailing edge on the underside of the primaries in flight, and that can be seen in the third photo as well.

Well, that all sounds good, but then I looked at some photos of wing specimens from the Slater Museum of Natural History at the University of Puget Sound -- here's a comparison of a first winter Herring Gull wing taken in March (top) with a first winter Thayer's Gull wing taken in October (Bottom) and you can see that these distinctions are fairly subtle. (The photo is right below here, but it may take a bit longer than the text to appear.)

http://www2.ups.edu/biology/museum/THGU-HEGUwing3.jpg


The more I peer at these wings vs the raised wing photo, the more I'm inclined to think the far side raised wing in Beth's photo resembles the Herring Gull wing -- the outer web is narrower than I'd thought and the dark color seems to leak over onto the inner webs, and it shows the pale inner primaries that the Herring Gull's wing has. Drat! On the other hand, the dark color on the primary wingtips is definitely not black, as it is on a 1st winter Herring Gull, and there's no hint of pink in the bill, which a 1st winter Herring Gull is said to be likely to show by now, whereas a 1st winter Thayer's Gull isn't.

Bother! I see why people have to struggle over these IDs. I'll have to work on this some more. Anyone else have some thoughts on the subject? (Maybe that DNA barcoding they're doing will eventually get them all lumped together as a single species and we won't be able to have this sort of fun anymore. :p )

There are some additional pertinent wing photos in the Slater's collection for study -- slide down this page to the heading Comparisons to find links to them:
http://www.ups.edu/x5906.xml

Hope you found the Little Gull! (By now it's Glad you found the Little Gull!)

[Ben Lamb]

Thanks to Betsy's and Perry's tips, and Beth's good eyesight, we did find the Little Gull today. It was almost across the lake near Winfrey Point, and so the photography is not quite as good as it was for the more cooperative Thayer's, but here it is:

http://farm1.static.flickr.com/173/418280230_c179a5b848.jpg

These two combined with the ring-bills, Bonaparte's and a couple of Franklin's floating out in the middle of the lake for a five-gull day.