Another Large Gull SP., Chiayi County, Taiwan: Another thayeri wing pattern. (1 Viewer)

[SteveMM]

I was more than willing to accept that Individual #1 (http://www.birdforum.net/showthread.php?t=339498) could only really be a vegae with a thayeri-like P9. The most obvious plumage detail 'out' for thayeri seemed to be the absence of a 'string of pearls' through the outer primaries (which no self-respecting thayeri would leave home without). Given that, then, what am I to make of my latest wingtip outlier, a bird which doesn't really seem to have the same problem!

Also, it must be of interest to someone out there that, from a sample of just five pale-mantled/pale-end vegae-types this winter, two now have had such oddly-patterned wingtips!

Any comments on this bird welcome. I'm far less convinced that this one is some kind of vegae, but still am not at all sure exactly what it is!

 

[SteveMM]

More of this gull. The attached photos are of the bird with taimyrensis. It is clearly paler, perhaps smaller, with a shorter squarer tail and duller bare parts. These birds are moving into a patch of strong sunlight which is exaggerating how vivid the bare parts look (which may account for the legs, which don't look right on their own but do look better when compared to just how vivid those of taimyrensis look).

The last photo is the wingtip of Individual #1 (taken three weeks ago about 50 km further south) for comparison.

 

[lou salomon]

if it wasn't for the completely pale iris and the fairly high and bulbous bill i'd readily call this a thayeri. with these i'm a bit reluctant as neither bill nor iris colour are typical (but possible). it has a lot of black on p9 also.

 

[SteveMM]

if it wasn't for the completely pale iris and the fairly high and bulbous bill i'd readily call this a thayeri. with these i'm a bit reluctant as neither bill nor iris colour are typical (but possible). it has a lot of black on p9 also.

Hi Lou,

Thanks again for the comment. I do see what you mean about these two features, which is so frustrating given that the wing looks so good. I can't do anything about the pale eye, but the bulbous bill may be being accentuated by the fact that the bird has a fish in its mouth (so the bill is slightly open in some shots). It looks decidedly better as it moves away, though my photos get poorer as it moves into stronger sunlight.

As you say, all of these outlier features are possible in Thayer's Gull, but all in the one bird would be strange. I have to wonder if this would be stranger than finding two thayeri wingtip 'unknown' gulls seemingly out of range and within weeks of each other, though!

 

[SteveMM]

Slightly off-topic, but I found these photos interesting. This is the first winter I have found thayeri-like wingtip patterns on what I assume to be vegae (two birds for me so far). Hong Kong seems to have one now!

http://www.hkbws.org.hk/BBS/viewthread.php?tid=26186

 

[SteveMM]

Quite remarkably, this elusive individual showed up again today (and in very different light conditions). From its heavy bill alone it is clearly not a Thayer's Gull (so good call, Lou). However, it's also not an obvious Vega Gull. It's shape is also rather odd - broad-looking rump, short tail and rear end, shortish and rather broad, square wings, bulbous head, neck, and chest.

Anyone care to suggest parent species?