Update: January 23, 2001 -
He's back! photos and discussion for January
2001 (with link to a possible sighting from even earlier,
plus a revealing page of specimens from
the BMNH). Update: July 18, 2000 - Check
the birds from Oman (with an image
of the Corpus bird thown in for comparison); plus a new page of
direct comparisons to birds from the Middle
East. Update: March 28, 2000 - a
few new images are added at bottom of the page. Updated Feb 27, 2000: added
a link to a comments-received section and revised my final thoughts
(at the bottom of this page). Updated Feb 22, 2000: added
more images taken Feb 18, plus adjusted comments based on detailed
conversation with WIllie Sekula and after reading c. eight private
replies about this bird; I'd like to add a separate web
page containing all the replies, so PLEASE tell me if you prefer
that your comments should be anonymous!
This large gull was at Corpus Christi Landfill, Texas on February
12 and 18, 2000 (photos by Willie Sekula; one video-grab by John
& Barbara Ribble):
- note that in the above image P9 is displaced and is below and
inbetween P10/P8 (its small mirror is visible directly below the
apical tip of P7)
Note the leg color compared to a first-basic Ring-billed
Gull here in the top-right corner:
- in the field the legs were pale flesh with some grayish tones
around the joint and a more yellowish tone to the front of the
tarsi - very similar to that seen on a significant number of adult
smithsonianus in Texas.
- it is a somewhat long-legged individual, and the very short
tail in combination with long wings (tail-tip a bit shorter than
apical spot of P6) create the classic rear-end structure of the
Fuscus group (fuscus/intermedius/graellsii/heuglini/taimyrensis).
Note also the clustering of dark streaking on the lower nape.
- the eye was described as "amber" from a distance,
and in close-up it can be seen to be a bit darker than the usual
very pale lemon color of adult graellsii - caused by a
scattering of dark flecks in the yellowish iris; the orbital ring
was described as blood-red. The bill is unremarkable, without
a significant gonydal angle and looking either longish or compact
depending on the view.
- It clearly has a large amount of black on P5 plus a smudge of
black on P4 (see first image), a fairly large P10 mirror that
does not reach the wingtip, and a tiny mirror on P9. P8 seems
to have no gray tongue on the inner web, yet the basal "black"
of Ps 10-7 is not sharply set-off against the gray, but instead
merges into it a little, in the manner of Slaty-backed Gull. No
flight-feather molt is evident (but P10 may not be fully grown).
- mantle tone was described as a bit paler than on the one adult
(presumed) graellsii seen that day, and one observer felt
it was on the pale side for most LBBG-types seen in Texas. Variable
and extreme lighting conditions in Texas can seriously hamper
the perception of mantle tone, and the most reliable means of
assessing this is to compare it to Laughing Gulls (LAGUs) at a
similar angle to the sun - this bird was just fractionally darker
than nearby LAGUs, and thus within the range of variation of graellsii/heuglini/taimyrensis.
The observers recount that it was a striking bird, the size
of a large smithsonianus (many nearby), and very different
from an adult graellsii seen at the same site that day
(I saw an adult presumed graellsii at this site on Feb
21, 2000: it still retained the normal extensive winter head streaking
and was clearly at least one shade darker than LAGUs - maybe more):
- in the above image, Photographic Size Illusion is making the
more-distant 1B smithsonianus look BIGGER than it really
was!
So what is this gull? I feel that the very short tail and long
wings are against this being a Kelp x Herring hybrid (or indeed
any combination that are not BOTH long-winged/short-tailed). While
graellsii has this rear-end structure, the tail normally
falls between the apical spots of P6 and P7; intermedius
usually has the tail-tip level with the apical spot of P6, while
fuscus (and heuglini/taimyrensis?) often
have the tail-tip falling short of the P6 apical spot. Clearly
the mantle tone is wrong for fuscus or intermedius,
as are the longish legs. Heuglini typically are slightly
larger than graellsii, have longish pale yellowish legs
that often have fleshy tones, a mantle tone closer to intermedius
(but there is much overlap with graellsii), black to P4,
one small/medium mirror on P10 that is well-separated from the
tip ( a small percentage have a larger P10 mirror and a tiny one
on P9), and eyes that frequently are not clearly pale. Taimyrensis
- the heuglini-like population breeding south-west of the
Taimyr Pensisula of central Siberia - is an enigma; there are
a small number of birds seen in the Middle East and east Africa
(India?) which have previously been pigeon-holed into this
form; these birds are mostly similar to heuglini but: tend
to be larger (HEGU-sized); have a paler mantle (similar to the
pale end for graellsii); have even longer-looking legs
that are mostly pale fleshy-pink (with some yellowish tones);
have a longer, paler bill with little or no gonydal angle (and
often with black on both mandibles at the gonys); eyes averaging
paler; a larger P10 mirror (and more frequently have a small P9
mirror???); and perhaps more often only a small black mark on
P4(???) - for now I'll call these birds "Big Pale Heuglinis".
From replies received, it seems that the form now regarded as
true taimyrensis winters exclusively(?) in eastern Asia
(s. China, HK, some to Korea and a few to Japan); this form has
yellow or even orangy legs (never pinkish), and is white-headed
by February, and experienced observers have ruled this out for
the Corpus bird.
I would greatly appreciate any further feedback
about this bird and/or about taimyrensis or the "Big
Pale Heuglinis" from eastern Arabia and India - thank
you.
Below is a photo by Mike Hill from Bahrain (date unknown, but
based on plumage, I'd estimate March), showing what a "Big
Pale Heuglini" looks like:
- the primary pattern of this bird is remarkably similar to the
Corpus Christi bird: the black "spacer" beyond the large
P10 mirror is about half the length of the P10 mirror; P9 has
a small mirror positioned just beyond the apical spot of P7. The
separation between the apical spots on P5-9 is identical: P6-P7
and P7-P8 are similar and longest; P5-P6 is about 2/3 of these;
P8-P9 is about 1/2 these. Note that the Corpus bird has P10 shorter
than P9, which may just reflect that P10 is not quite fully grown.
Compare these points with the Corpus bird - and remember that
the harsh lighting in Bahrain causes all mantle tones to appear
darker than normal (look at my images of cachinnans, barabensis,
and heuglini from there): Public feedback about this bird from experienced gullers is
availible here.
So, my summary is that the Corpus bird could be: A) a weird hybrid
(what parentage would produce this combination of plumage and
structural characters?); B) a most unusual truegraellsii
(do such birds exist?; how often does truegraellsii
occur in North America?); C) a "Big Pale Heuglini".
While B) is the safe call (and perhaps it is best to leave it
unidentified for now), I am still leaving the door open for C)
- but could these birds themselves be a stereotyped hybrid of
heuglini and argentatus or birulai???. Given
the migration direction and distance undertaken by birds breeding
between the Kola and Taimyr Peninsulas, any individual heading
in the reverse direction would most likely end up in the southern
US or Mexico for the winter. Of course this is all speculation,
but given the growing record of birds seen in southern North America
that originate from the interior of Eurasia (Citrine Wagtail,
Brown Shrike, the Finnish-banded Black-headed Gull, etc), it may
not be as unlikely as it once seemed.
The photos below were taken March 7, 2000 by Mel Cooksey:
