pale heuglini/ taimyrensis or lookalike?
Most gull photos I receive to comment on usually fall into one of several ‘expected categories’. Not this one. Dean Nicholson’s regular search of the gulls flocks in Lincoln’s southwest corner (North Hykeham) produced this bird.
Seen briefly on 16th March 2012, very well on 19th March (most photos taken) and again briefly on 21st March and not since. It seemed to associate most especially with Lesser Black-backed Gulls (ranging from typical adult graellsii to black looking intermedius types). Dean described it as:
“An adult – too dark mantled for michahellis or cachinnans but too pale for even the palest graellsii (and with a noticeable blueish tinge), head and hind neck streaking rather odd for time of year, the hind neck streaking forming a ‘shawl’ like on a winter Caspian…no other adult LBB present today had as significant streaking as this. pics shows the mantle tone in comparison with argenteus Herrings and graellsii/intermedius LBB’s.
The bird had single white mirror on p10, there was a thick black band on p5
Although not in the same frame for direct comparison there was a 3W michahellis present today which was seen to be obviously paler than this bird. It really didn’t fit anything particularly well……so what is it?”
and he went on to say:
“and there are some frighteningly close Heuglin’s (of the form taimyrensis) pics knocking about the various gull sites(!)”
A couple of days after main sighting he comments:
“Spent 2 hours this afternoon grilling c40 adult LBB’s and was quite surprised at just how worn the majority of the birds primaries were compared to my bird, most birds showed reduced white tips where the ends had started to wear and a couple of birds already showed totally worn tips making the primaries appear all black. Similarly the head streaking was nonexistent on all but 2 birds which showed just faint ‘pencil thin’ lines around the eyes on to the crown….neither of these birds showed any streaking to the hind neck at all.”
Well I agree. Indeed I was immediately impressed by the birds’ appearance. That is, to me, its looks frighteningly like some pale heuglini- or dare I say example of taimyrensis (whatever that is). In terms of the bird’s appearance:
* droopy billed, dopey look of some ‘Siberian Gulls’ (hard to explain!)
* streaking still present on head, especially concentrated on lower nape
* upperpart tone between graellsii and michahellis
* only one white mirror in outer primaries and at notable distance from feather tip
* extensive black appears to be cover most of p10-p8 and good amount seemingly on p4
Yep. That combination to my eyes is very like taimyrensis. Whether it is one or not is another matter. Now some may be inclined to come rushing in and say that taimyrensis/pale heuglini) only head southeast from breeding ground to winter in Southeast Asia. The great majority of the population may, but I have never been convinced that they all do. The presence of similar birds in the gulf in winter (pers obs, a while back so probably need a refresher) and passing through Azerbaijan in autumn (C. Gibbins pers comms) suggests otherwise; and why not? Most fuscus head SE- but not all (some go SW). Most mongolicus head east- but not all (some go west). I think most thayeri head SW but not all (some go SE!).
Have a look at the pics and the combination of characters. Interesting no? Certainly got my ‘possible vagrant gull taxa’ juices flowing.
All photos, North Hykeham, Lincolnshire, 19th March 2012 by Dean Nicholson
bit of droopy-billed, ‘dopey’ look. streaking still present concentrated on lower nape
looks like black is present at least on outer web of P4
same features again
all black looking p10- single mirror on p10 and of noteworthy distance from feather tip
’tis the bird on the right- compared with 2 adult Lesser Black-backed Gulls on left