Thayer's?

[Wetlander]

Not great photo, but is the little one with profile to viewer a Thayer"s? It was a smaller bird with a smaller bill. GW Hybrid right next to it for size reference.

[Deleted]

Hey, you just know that someone is going to sign in and say it's hard to tell.

Just looking at what's there, I think the two most likely options are Thayer's or California Gull. The general impression makes me think first of California, but Thayer's is also a reasonable option. For Thayer's I would expect a bit more rounded head profile, and perhaps a bit bigger size of bird, but there is enough variability in those characteristics of either species to allow for both possibilities for this individual.

To get into really picky details, it's sometimes said that our knowledge of Thayer's Gull is largely based on characteristics that fit Thayer's females more than males, so that most gulls we identify as Thayer's are female Thayer's. A Thayer's male would presumably have a less rounded head, flatter and more 'fierce' looking (more like Glaucous-winged, Herring, etc.), but it would also be a slightly larger sized bird. So I'm thinking if this is a Thayer's female its head is too fierce looking, and if it's a Thayer's male it's not a big enough bird. But I'm only asking out loud here, not pretending to know the answers. I'm hoping someone else will say what they think, too.

Did you by any chance get to see the leg colour? That would be fairly definitive in separating Thayer's (pink legs) and California (yellow legs) Gulls.

By the way, were the foreground gulls Mew Gulls? (I'm just testing my over all impressions again.)

Stan Olson
Abbotsford

[Wetlander]

Hey Stan, thanks for the help.
I'm still a novice at gulls, and don't know if the foreground birds were mews. They didn't move much, but they did look small. At first I thought this individual might be a mew, but like you said, it has that fierce look around the eye.

I looked through the photos I took of this individual, because I (once again) forget to pay enough attention to the legs. I found one photo with what looks like yellow legs.
I will also include this 3rd photo, as these 3 were the only useable images I got. What do you think, California?

[Gord]

I almost get a Ring-billed Gull feel on the upper picture with a juv Mew Gull behind. The legs on the adult look yellow and back looks pale in the picture. But as Stan pointed out, looks a bit bigger. I would exclude California Gull as their backs are a little darker. Aside from Glaucous-winged X Western hybrids, they are the next darkest backed common gull from Western Gull. Among a flock of pure gull species, California Gull's stick out. I think Thayer's would be a thought but still considering Stan's comments.

All the little guys Im pretty sure are Mew Gulls.

Love the digiscoping! Glad to see you're enjoying your new scope. That will help plenty in gulling. Keep at it! Id really enjoy seeing if we want to get a group together to enjoy looking at gull flocks next fall-winter.

[Deleted]

You're right, Gord, the closest of the three gulls in the upper photo (the photo with no other gulls in the foreground) does seem lighter on its back. I'm not even sure that's the bird we're discussing, but I'll assume it is. I didn't put a whole lot of weight on the back colour in my earlier post, because the back-lighting in the photo is tricky and even a slight change of angle in the way the bird is standing can produce a shift in colour appearance. In this upper photo the bird in question does look to me to be standing with its back and sides at a different angle and slope than is the gull on the right hand side (whose actual upper back looks white from the sun, with its sides contrastingly dark). But that is largely subjective. The digiscoping vignetting effect can also play some tricks with shading, of course.

My comments were based more on the structure of the bird in the first photo, which shows it well in profile. Granted, the lighting can play tricks with the way structure appears too.

However, I don't agree that California Gull would be darker than all gull species expected here except Western or some hybrids. Howell and Dunn's Reference Guide to Gulls of the Americas has a very useful table on page 26 showing Kodak Gray Scale values for upperparts of adult gulls recorded in the Americas. The Kodak Gray Scale values in the whole table run from 0 (Ivory Gull) at the light end, to 17 (Olrog's Gull - a gull of the SE coast of South America) at the dark end. Slaty-backed Gull, the darkest backed species likely to be seen around here, is shown ranging from 9.5 to 11.5.

They show nominate California Gull (Larus californicus californicus) ranging from 6 to 7.5 on the Kodak Gray Scale, the same range as Mew Gull and at a similar range as hybrid Glaucous-winged X Western (6 - 8). Western Gull (our northwestern subspecies occidentalis) is considerably darker, ranging from 8 to 9.5.

The other subspecies of California Gull (Larus californicus albertaensis) is shown ranging from 5 to 6, an identical range to Thayer's and Glaucous-winged, and lighter than Mew (6 - 7.5). Given that the non-breeding ranges of the two subspecies of California Gull don't seem to be very well differentiated, and both can be present throughout the species' wintering range (Howell & Dunn, p. 396), the back of an adult California Gull of the albertaensis subspecies seen here should be a shade of gray similar to Thayer's and Glaucous-winged and noticeably lighter than most Mews, according to Howell and Dunn.

So I don't think California Gull can be excluded in this case on the basis of back colour in the photos. The yellow legs shown in the two photos do eliminate Thayer's and other larger gulls, of course.

By the way, Ring-billed, Kumlein's and American Herring Gulls are each listed as ranging from 4 to 5 on the scale.

I agree, Ring-billed Gull is a possibility too, but structurally it just doesn't look right for a Ring-bill, to me (head a bit small, bill a bit long and a bit thin), at least in the original photo, which shows it standing in a straight-on pose. I can't make out a typical ring on the bill in the photos, either, but that may be more an artifact of my aging eyes than of the actual bird.

But that's the challenge -- the ones that aren't simple, with no easy answers, are the ones that are fun. We don't usually have to look too far to find a gull that fits this category.

Hey, I could well be wrong on this one. It wouldn't be the first time, or the last.

Stan

[Gord]

Stan, great information on the scale of back colours. Found that very informative!

Great discussion and so much learning opportunity. Too bad gull season is winding down.

[Wetlander]

Stan & Gord,
Thanks to both of you for input. Sorry I should have been clearer, yes Stan, the bird in question is the foreground bird in the second photo. Thanks for your info... I will be re-reading this for awhile. I have to get a good guide on gulls so I can get some of the fine points. I think you're right, the back colour is tricky, the lighting was murder and most of the photos I took were totally unusable. My camera wasn't a good fit with the scope and most of the photos I took trying to isolate this individual "flaired out".

And Gord, hard to tell from my photos, but the bird in question didn't have a ring on the bill, but a red spot. Thanks again and I hope to get better at digiscoping and get better photos for IDs. And Yes!!!!! If I can at all make it, I would love to take part in Gulling workshops.

[Deleted]

No problem. Maybe the photos weren't as good as we would have liked, but that is often the reality of the situation. Gulls don't often pose with ideal lighting. Often they create equal difficulties in real life because of bad lighting or other issues.

I've tried digiscoping off and on in situations where it would have been great to get a good shot, but mostly it doesn't work out with my equipment either. Fortunately the Delete button doesn't have a debit card reader attached, and one can just keep shooting and hope something will work out, and trash all the rest.

I don't pretend to be a gull expert by any stretch, so don't take everything I wrote as the final truth. Don't discount your own observations. Build up your own experience with gulls. If you ever get a chance to go gulling with some of the Vancouver birders around Boundary Bay or wherever, go for it. Many of them know tons more than I do.

I hesitate to suggest which gull guide is best, but I personally find the one by Howell and Dunn (referred to in my earlier post) very helpful. A friend of mine thinks Gulls of North America, Europe and Asia, by Olsen and Larsson is better. The older standard, Gulls : a Field Guide to Identification, by Peter Grant (second edition) seemed to me like an amazing resource when I got one a few years ago, but it is now dated and the other two books now surpass it, and they show how far serious birding has come in recent years.

Let's hope for large flocks of gulls in the central and eastern valley again this coming fall and winter with lots of learning opportunities.

And seriously, I'm not sure that's a California Gull. If someone wants to make a case for another species, please go for it. There are weaknesses in my case. The yellow legs eliminate larger candidate species, and the relative size comparison is quite helpful, but beyond that, the main foundation of my case is the structure of the head and bill in the one photo, and the harsh lighting can distort that just as much as it can the other factors mentioned, such as upperpart colouration.

Stan