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Gull ID, Salton Sea, California, USA, Earth (1 Viewer)

DarkFireFalcon

Well-known member
I'd like to solicit some advice on ID'ing this large dark mantled gull from the north end of the Salton Sea in California, USA. Yellow-footed is probably the most likely large dark mantled gull, but Western (and even Lesser and Great Black-backed) have been recorded as well.

Here's my description:
In comparison to the nearby California Gulls it was large and chunky, with a hefty looking bill. The mantle color in the later afternoon light (about an hour and a half from sunset) looked darker than the nearby California Gulls. The eyering was clearly yellow through my scope, and the gape was a fleshy pinkish. The legs were... confusing. The pinkish-yellowish color depicted by the photos is pretty much what I could discern in the field. In flight, the tail was solid black and the upper-tail coverts appeared completely unmarked. The photographer mentioned that the camera was making the mantle appear slightly darker than it looked in the field. I think these shots were adjusted somewhat, to try to show the mantle as accurately as possible. At all angles it was darker than nearby California, but not shockingly so. The photos do show noticeable contrast between the mantle and primary tips.

When I posted it to the Facebook Gull group, the first response was that it looked like a Kelp Gull.. I've no experience with this species (but to me, it seems too pale mantled). My tentative ID was Yellow-footed Gull, but I've limited experience with that species, and the dark eye bothers me. I'm curious to hear what others think.
 

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DarkFireFalcon

Well-known member
The tertial crescent doesn't seem particularly large, and the feet seem too pale for Slaty-backed, but that's another species I've zero experience with. I'm leaning towards Western right now.
 

lou salomon

the birdonist
to me it looks good for yellow-footed. structurally and plumagewise. why considering extreme vagrants when then bird looks ok for the default large gull of the region? paler legs are just a sign of immaturity as are the dark irides. both leg and eye colour being among the more variable traits in large gulls..
 

DarkFireFalcon

Well-known member
That's Lou. I've no idea why Kelp Gull was originally suggested.

I was originally hoping to get feedback on how Western Gull could be ruled out, which are rare but regular at this location in the winter. Another experienced birder has reported (presumably) this exact bird at this location as a Western Gull. Some people have told me it looks like a Western Gull, others Yellow-footed, some citing the same exact marks. One person said the bill is too small for Yellow-footed, while another cited the massive bill as being good for Yellow-footed...

Are there any good diagnostic ways to tell a 1st cycle Yellow-footed from a 2nd cycle Western? From what I've read, the unmarked uppertail coverts contrasting with solid dark tail might be diagnostic for Yellow-footed. Is that true?
 

MrBiffa

Well-known member
Lou you are so good at this after a while I'll get the hang of gulls, you're right with yellow footed after looking at a picture, you may have seen me post this before but I'm only 13 so need your amazing expertise to help me, you're always right ;)
 

lou salomon

the birdonist
sorry darkfire and - there you go, biffa, - i have to revise my ID. this bird can neither be a 1st cycle large gull nor a 2nd alternate YFG which would be more advanced (hardly with brown wing coverts).
so, i'm swaying to 2nd cycle (alternate) wymani western gull - dark mantle in this subsp. normal. i had thought i see a yellow hint to legs which would be very unusual for western but there is not much of yellow visible and that chunky bill can well sit on a male wymani. much better choice...sorry again. western is a good bird for salton sea! but i have to admit i have never seen yellow-footed in flesh.
as for yellow-footed: have a look at 3 age classes with a dark eyed adult type here: http://www.kiwifoto.com/galleries/birds/yellow_footed_gull/; more YFG: http://www.anythinglarus.com/2010/08/yellow-footed-gull.html
 
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DarkFireFalcon

Well-known member
Thanks Lou!

In the field, I did note that the legs looked pinkish from some angles and yellowish from others, but on such a young gull, I'm not sure how much that matters..

I was curious, because I couldn't find any pics of 1st or 2nd cycle YFG with a back pattern that matched mine, but I have seen Western's with similar patterns.
 

smiths

Well-known member
Hi,
the confusion is very understandable. I had to put quite some thought in this one, but in the end I feel it is most likely a Yellow-footed Gull.

In any case, this is a second-cycle gull (so second summer plumage), because the primaries are broad, fairly rounded and blackish. If this was a 1st-cycle bird, the primaries would still be juvenile, looking narrow, brown, pointed and clearly worn.

Although the second pre-alternate moult (i.e. the moult to "second summer plumage") is usually extensive in Yellow-footed Gull, and may even include all rectrices and up to 8 (!) primaries, there is variation and a few birds acquire only a 'retarded' plumage.
See plate 32.19 in Howell's Gulls of the Americas for a good example.
Therefore, I think the moult state and the plumage of this bird may fit either species.
In addition, there is variation in bill shape, and not all Yellow-footed Gulls have an obviously bulbous bill.

While I have seen adult Western Gulls with yellowish legs, I am not aware of this colour already being present in 2nd cycle. This seems to be a strong indication of Yellow-footed Gull, which is also the more likely species at this location.
 

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