The bird was clearly not a typical michahellis on structure; stocky yet large (even "stumpy"), particularly large- and slightly rounder- headed, short legged, relatively broader and shorter winged (making argentatus less likely), and with a deep but not too long or obviously hooked bill- all looking better for a bird from the "Atlantic" at least! Structure is usually over-stated in LWHG identification as sexual dimorphism, individual variation, physical condition, external factors like wind and temperature, and activity or posture all have effects. At least here there were sufficient numbers of LBB L.f.graellsii, GBB L.marinus, Herring both argenteus and nominate, and up to 6 YLG presumably "typical" michahellis from the Mediterranean for comparison, and the bird was watched over an hour in varying situations from aggressive encounters to loafing and preening.
|Notes and sketches of the probable "2nd w.- 2nd s." Azorean Yellow-legged Gull L.(m.) atlantis, Stanwick Lakes, Northants, 9/5/2015. Please note the head and bill are drawn too large and long respectively, and the "rear" end too short!|
|Prob. 2w-2s L.(m.)atlantis, Stanwick Lakes 9/5/2015. "'Phone-'scope" shot- note over-exposure in low sun. The birds legs were more strongly washed yellow- particularly rear and sides than is apparent here.|
To my mind the greatest difficulties arise when attempting to rule out other Atlantic populations of YLG with Madeira being the most problematic (M. Ahmad, T. Worfolk etc. pers.com.), and the more likely- yet more vague and un-proven- possibility of hybrid graellsii x argenteus! The latter do appear to be increasing alarmingly as these taxa colonise more inland sites, and I have seen at least 3 presumed hybrids of this age on the Hayle this winter- the season when the typically heavy, extensive and coarse head and body markings of either parent species are one of the best clues to their identity! Luckily the Stanwick bird retains extensive fine ( though faint and bleached and hard to see in bright sunlight) streaks forming a cap across the crown and upper nasal feathering, and enough, slightly broader streaks from the chin back below the lower "face" and ear-coverts to define what must have been an impressive "hood" when these ff were fresh! There are scattered broader, quite pointed streaks mostly retained on the lower hind-neck which is neither inconsistent with atlantis - or any other 2nd year, but the relatively extensive (though again faded) grey clouding on the lower breast and belly are far more typical of Azorean YLG of this age and season- a feature first brought to my attention years ago by M Ahmad as the "Dunlin-patch"! I have even seen these ff retained on a (presumed and as yet un-submitted) 3rd calendar year atlantis completing it's moult to 3rd winter at Sennen, Cornwall in October 2010! This resulting combination of body markings largely confined to the lower belly and head in the form of a neat hood makes atlantis unusual in having an arguably distinctive appearance at this age- which in almost all other LWHG taxa is a stringer's paradise of variation and contradiction!
There are subtle features shown by atlantis beyond the head and body markings, but- as is always the case with LWHG- these are largely only "average" differences which can be shown by some individuals of related taxa. Some of the following are probably not even recognised as features of atlantis at all but are based on my own observations- so now would be a good time to confess that my field experience of this taxon is entirely based on presumed examples in this country! This makes for a grand total of 4 birds I am "happy" with (not including this particular 3rd cal. bird), and 2 more "probables" that for different reasons I would not be happy submitting as definitely of this taxon- but important to file for future reference nonetheless! It also makes for an arguably shaky foundation for any conclusions I might draw let alone put before others to read, but there is an ever growing mass of excellent photographic material on atlantis (which I have devoured- and am extremely grateful to those who have provided it!). I have also been given access to more by friends who have made it to the Azores- Mashuq Ahmad in particular- and have managed to tear themselves away from the grotty, totally predictable and entirely irrelevant selection of doomed Yankee vagrants for long enough to snap some larid! More to the point of this post (which may possibly evolve into an entire "dossier" to be passsed on to the BBRC!) I have seen and grilled 1000s of michahellis from the UK, France, Spain and Bulgaria,virtually year-round (November and June being confined to birds in the UK) so I hope readers will bear with me.