March 14, 2012:
This First Cycle-type gull with the characteristics of Slaty-backed
Gull (Larus schistisagus) was first found and photographed by Jon McIntyre on February 23, 2012 on Mustang Island, Nueces county, Texas. It was then seen and photographed again by Clay Taylor on February 26 at the Packery Channel Bridge (c. 10 miles south of the original spot). McIntyre was using a long-zoom digital point-and-shoot, while Taylor used two different types of DSLR - hence the different characteristics evident between some of the photos.
Features that point towards SBGU (a female based on the smaller head and bill compared to male SBGUs):
1) structure 1: the legs are fairly wide-apart and shortish, and there is a bit of a droop behind the legs plus a strong chest "keel" and long neck - all combining to impart a vaguely goose-like impression in some stances.
2) structure 2: fairly even bill depth with small, shallow gonydal angle; rather steep angle from bill base up forehead; peak of crown over eye with gentle domed crown shape. Also in flight note the very obvious hump in the upper back.
3) legs strongly pink -
more pink than the adult American HERG in the same photos (some HERGs can have strongly pink legs - but it is a typical feature of SBGU).
4) head with eye placed slightly forward of center, surrounded by a small dark patch and with a short dark line extending back from the eye; the crown and forecrown with obvious, cleanly-demarcated dark streaks.
5) dark tail lacks ANY barring - instead having pale specking scattered strongly on the base of R6 and less-so on the base of R5, plus variable "soft" pale tips to the Rs - one of the classic patterns for SBGU and not found in any HERG or GWGU.
6) primaries and secondaries with clearly paler inner webs than outer webs (contrast less distinct on overall paler inner Ps); tips of outer Ps worn such that darker tips from below are vestigial; darker tips of inner Ps faded such that vestigial from above - but present. In flight the outer Ps (plus their coverts), secondaries and tail are similar in tone and darker than the rest of the upperside.
7) from above
all non-worn greater, median, and larger lesser secondary coverts very pale on large inner web, slightly darker on thin outer web plus with similar-toned subterminal mark across both webs - overall effect is of a very pale inner wing with rows of darker spots.
8) from above all primary coverts match their overlain primary in tone and pattern (i.e. paler inner web); alula feathers slightly darker - the darkest part of the upperwing.
9) on standing bird the folded primaries are the darkest part - pale brown but slightly darker than the exposed secondaries, tertials, and the tail; visible outer Ps with pale fringing at tip - but ware/fading renders this less useful.
10)
dense dark markings on uppertail coverts and undertail coverts typical of all large North American gulls plus SBGU.
11) the rather pale gray mark visible between the tertials in flight is not a concern, as many SBGUs in their first Spring seem to acquire paler gray blotching in the mantle/back/upper scaps area.
Here are McIntyre's photos from Feb 23:
FOR COMPARISON BELOW IS A SBGU FROM JAPAN IN MID-FEBRUARY:
FOR COMPARISON ABOVE IS A SBGU FROM JAPAN IN MID-FEBRUARY:
Here are Taylor's photos from Feb 26:
LINKS TO PHOTOS OF SIMILAR BIRDS FROM JAPAN:
note that the hot, sunny, sandy Gulf Coast beaches are different to the cool, cloudy, rocky coastlines that are the wintering grounds in Asia - bleaching and wear rates are much faster in the Gulf than in the eastern Pacific:
http://www23.tok2.com/home/jgull/DecSla/zDSCN1055.jpg - mid December
http://www23.tok2.com/home/jgull/080115/080115%20031_S.jpg - mid January
http://www23.tok2.com/home/jgull/SlaG1w01113/SlaG1w01113_3.JPG - mid January
http://www23.tok2.com/home/jgull/SlaG1w01113/Slaty1w.jpg - mid January; both are SBGUs - a nice demonstration of the variability in primary tone
http://www23.tok2.com/home/jgull/080115/080115%20122_S.jpg - mid-January; imagine this bird a month later and more sun-bleached and worn...
http://www23.tok2.com/home/jgull/080115/080115%20246_S.jpg - mid January
http://www23.tok2.com/home/jgull/040113/Sl_03.jpg - mid January; a darker individual but included to show what females can look like, structurally
http://www23.tok2.com/home/jgull/040113/Sl_08.jpg - Mid January; here's what the Ujihara's said about this bird: "A pale, advanced individual. This resembles somewhat Glaucous-winged Gulls. But its outer primaries and tail are dark in contrast to the rest. This type may suggest Glaucous-wingedXSlaty-backed as well, but I think this type is too common in Japan to be that, in comparison with the frequency of adults presumed to be the parentage. " - THEY DID NOT HAVE ANY MISGIVINGS ABOUT THE OTHER SBGUS LINKED ON THIS PAGE.
http://www23.tok2.com/home/jgull/070216/SLFL%20%2810%29.jpg - mid February
http://www23.tok2.com/home/jgull/070203/SBG%20%2810%29.jpg - early February
http://www23.tok2.com/home/jgull/070203/SBG%20%282%29.jpg - early February
http://www23.tok2.com/home/jgull/Sb1w_pCh.jpg - February
http://www23.tok2.com/home/jgull/Sb1s010427/Sb1s0104277.JPG - early April
http://www23.tok2.com/home/jgull/Sb1w010402/Sb1w010402_5.JPG - early April
http://www23.tok2.com/home/jgull/061101/Sb%20%287%29.jpg - November 1st; what would this look like in mid-February having wintered in the Gulf?
http://www23.tok2.com/home/jgull/061101/Sb%20%2812%29.jpg - November 1st; what would this look like in mid-February having wintered in the Gulf?
A page of birds from February 10th; in particular compare the tail pattern of the first bird to the TX bird:
http://www23.tok2.com/home/jgull/Slab1w010210/Sla1w01_2_10.html
Two pages of birds from mid March:
http://www23.tok2.com/home/jgull/050315/slaty.htm
http://www23.tok2.com/home/jgull/050315/slaty1.htm
A page of birds from early April - note especially the one with wings raised:
http://www23.tok2.com/home/jgull/Sb1s010402/Sb1s01_4_2Sa.html
A page from "eary Spring" - with primaries much paler than the TX bird:
http://www23.tok2.com/home/jgull/slaty_fa1w/fa_1w_slaty.html
http://www.birdskorea.org/Images/ID_Notes/Slaty-backed-Gull/image15fwslatynov22y2002gurya.jpg - a bird from Korea in November
http://www.birdskorea.org/Images/ID_Notes/Slaty-backed-Gull/image16bleachedfwslatymarch92003guryongpoa.jpg - a bird from Korea in March
