juvenile/1st winter Iceland and Kumlien’s Gull Identification

The Bridlington Bay Gull

Iceland Gull Brid. L 13.1.13

I have had a chance to review some work I did on these a few years ago *. This was based on literature search, examination of specimens from Greenland (Tring) and observation of Iceland and Kumlien’s Gulls in Britain, Ireland, Iceland and Newfoundland. Criteria were suggested for identifying out-of-range juvenile/1st winter Kumlien’s Gulls.

I have also received some illuminating correspondence following this post. The upshot is that the most  parsimonious explanation for the appearance of this 1st winter bird is that it is a Kumlien’s Gull. There are more obvious examples, so it’s reasonable to exercise caution.  Calling it   glaucoides/kumlieni thus indicating (in UK context) an interesting and unusual bird is reasonable. Calling it ‘just an Iceland Gull’, inferring that it is a standard/pure nominate glaucoides seems not to be defensible.

When I first saw the bird at Bridlington it was reasonably close. I could see straight away that it was an Iceland Gull. Lifting bins I was somewhat taken aback to see (what I would call) a Kumlien’s type pattern on the primaries. Despite having seeing annually 10’s of Iceland Gulls over 5 years in Ireland including small flocks of juv./1st winter birds,  I only saw this pattern maybe 2-3 times.

“So how do you identify a juvenile/ 1st winter Kumlien’s Gull?”

Criteria (with photos) written up in Birding World in 2000 * still, I think, hold up quite well. I am sure these will be rightly questioned and improved with current ongoing study but it’s reasonable starting point:

“an outer primary pattern that we believe constitutes an identifiable vagrant first-winter kumlieni (on current knowledge) is of a variable brown wash centred on the primary shaft, spreading onto both webs and extending almost to the feather tips. It is most commonly plain, not ‘mealy’ or spotted, although many show a small subapical mark. From February to April, the brown wash and subapical marks (if any present) fade or disappear on many individuals, leaving the outer primaries a rather plain creamy-brown or off-white thereby increasing the number of kumlieni that may be inseparable from glaucoides. Other tendencies- and the are only tendencies- of first winter Kumlien’s include a shorter primary projection, an earlier moult for some mantle and upper scapular feathers (sometimes from Oct/Nov) a darker bill in mid-winter, a more distinct [plain] tail band  and more contrast between the outer (darker) and inner (paler) primaries in flight on the more distinct individuals”

Peter Kristensen got in touch from Denmark. He helpfully asked the question the other way round.

“How do you identify a pure Iceland Gull (nominate glaucoides)?”

“Hello Martin 
Saw your post about an Iceland Gull. I just want to let you know, that we last winter made an article on the subject in Danish, but what we did was to find all material on birds we knew for sure was pure Iceland Gulls [nominate glaucoides]. This means lots of gulls seen in Northern Europe and Greenland but also the big collection from zoological museum in Copenhagen – this includes many hundreds and some date back to the middle of the 1800. What we wanted to find out is, how much variation is there in Iceland Gulls – especially 2nd and 3rd winter. I had the feeling, that places like Iceland and sometimes the Faroes are difficult places to be absolutely certain that a dark bird is really a pure Iceland, and I therefore disqualified such a bird in order to document how much variation there is in 2 and 3 winter Iceland Gulls. What we found out is, that there wasn’t any variation amoungst the many birds collected in Greenland – they were all perfect whitish looking Iceland gulls.
So we turned the way of documentation around, and said – how can you identify a pure Iceland Gull (as we think this is more interesting than the many hybrids/kumlieni). So, if your bird was a rare bird that needed acceptance from a rarity committee  I don’t think it would pass as a pure Iceland Gull – it is outside the variation we could find in our collections – not a lot but enough I think.
Best regards
Peter H. Kristensen”

Iceland Gull Brid. h 13.1.13

Iceland Gull Brid. k 13.1.13

Iceland Gull Brid. j 13.1.131st winter - not pure glaucoides Iceland Gull  ; ) -South Shore, Bridlington, 13th Jan 2012.

marchjuvenile/ 1st w Kumlien’s Gull, Connecticut, USA, March by Julian Hough. A pale bird with similar if slightly less well-marked/more faded primary pattern to the Bridlington bird. Of course knowing where every Iceland type Gull comes from in NE USA is uncertain. While there is the bewildering variation, all the birds in Julian’s area pass  as kumlieni. Julian comments “I would definitely be thinking of kumlieni for your bird since it would pass for that race over here in the US…I couldn’t get it passed as a dark glaucoides

Phone a friend

I asked some friends with plenty of experience and interest in the subject, for their impression of the Bridlington bird, based on my photos:

Chris Gibbins (studied bird’s in Newfoundland) “Wow…actually this is a great great bird.  More Kumlien’s like than I imagined! [from my verbal description]. Leave it with me to work on properly…”

Anthony McGeehan (studied birds in Newfoundland)

“Your bird could fit either ‘taxon’. I mean in structure: it could be a ‘Pretty Boy’ Kumlien’s. But what about plumage? There is a fairly heavy pigmentation on its chequered tracts – enough to push the limits for Iceland? But I don’t feel safe on that ground, given the variation within Iceland. For me, the crunch is the patterning on the primaries. On even a well-patterned Iceland (some have a soft pattern, just like Glaucous) the strength of the pattern seems to have an upper limit. That upper limit consists of (low contrast, of course) a pale rim on the primaries with a little ‘diamond’ of dark nestling at the apex of the subterminal rim (on its inner edge). I’m sure you know what I mean. You could describe it as an ‘anchor mark lite’. Anything more than that puts the bird into Kumlien’s territory. Obviously I could be wrong and there may be a tad more dark patterning that occurs in ‘extreme’ Iceland? I think the last sentence is speculation. So, on your bird, given the ‘excessive’ dark patterning that goes beyond my own limit, I’d be calling it Kumlien’s.”

Ian Lewington would have been very pleased to find it! Felt different to annual juv. Iceland Gulls in Oxford and almost all juvenile Iceland Gulls seen over several years in the west of Ireland, where most looked of a ‘type’ with all white wing tips. Verdict: most likely a Kumlien’s.

Iceland Gull, 1w, Barmston, E Yorks, 7 Jan 13 br1st winter probable Kumlien’s Gull, Bridlington Bay, 7th January 2013. Brett Richards

*Garner, M., Kolbeinsson, Y. & Mactavish, B. 2000. Identification of first-winter Kumlien’s Gull and the ‘Whitby Gull’. Birding World 13(3): 116-119

8 thoughts on “juvenile/1st winter Iceland and Kumlien’s Gull Identification

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  2. Martin Garner

    I agree generally with the conclusions of this paper in terms of what Kumlien’s is http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2000.tb01234.x/abstract and have thought that Kumlien’s was result of recent introgression of thayeri genes into glaucoides pop. for yrs. How you interpret that taxonomically is open to debate I think. The fact that thayeri and glaucoides were once separated well defined populations seems impt. Thayeri on main wintering grounds still appears consistent in appearance. Are they 1 species, 3 taxa, or 2 species and hybrid swarm? I hold the latter view akin to GW Gull and Western Gull and the ‘Puget Sound’ hybrid swarm equivalent is Kumlien’s. Presumably it will evolve though as glaucoides has priority as taxonomic name, but what if pure glaucoides becomes completely swamped by melanin (which is potentially where it’s all headed.). Then you would have no glaucoides… So indeed all ‘melanised’ glaucoides (= Kumlien’s) that we see here are part of dynamic change in populations which I think is very interesting. all good fun! Martin

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  3. Peter de Knijff

    What you have to keep in mind in this context is the simple fact that all Nearctic large white headed gulls (LWG) are genetically speaking extremely closely related and very hard, if at all, seperable based on DNA only. For that reason, we (Liebers, Helbig and myself) prefered to speak of the Beringian clade in our Birding paper, because that is where they all came from. Exceptions, of course, are Yellow-footed and Western, which are much older taxa. Add to this the repeated influx of Paelarctic gulls, such as Great Black-backed and, more recently, Lesser Black-backed. And, we also have no clue how exactly Glaucous Gulls in the Nearctic relate to their Palearctic brothers.
    The way I see it now, is that it will be, for the time being, extremely hard or even impossible to define species and/or subspecies level among LWGs. What is possible, of course, is, as Martin and others advocate, to try to get a very detialed picture of plumage variation of all ages, and at least be able to seperate more or less distinct populations of birds sharing many characters. What these populations represent, will remain a mystery and require very large and very detailed genetic studies.
    The Kumliens discussion remains, for the time being, blurred by tick-list wishes which are irrelevant from a biological point of view. For me, they represent one of the ultimate identification challenges, and therefore big fun in the lab and in the field, tick or no tick.

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  4. Dave Britton

    Hello, Martin. Two thoughts (1) Are you still ambivalent re the 2000 Whitby bird? (2) Have you seen Roy Lyon’s flight pic of the Barmston bird (on Hull Valley Group web site)? The venetian blind appearance of the primaries is reminiscent of Thayer’s Gull (no other features of Thayer’s clearly). The Whitby bird seemed to lack this feature. Would you think this is a pro Kumlien’s feature given the close association of Kumlien’s and Thayer’s, many people thinking the two might constitute jointly a separate species from Iceland Gull? Dave Britton

    Reply
    1. Martin Garner

      Hi Dave.

      Probably I would be better using the word equivocal about the Whitby bird. as in the original Birding World article the possibility that it was a Kumlien’s Gull always remained, the main point being that aware that some nominate glaucoides (from specimens) had coarser marks) then that possibility couldn’t be ignored. However birds with PLAIN brown marks almost reaching the tips of outer primaries seemed both then and now to be highly indicative of juv/1st w Kumlien’s. We included photos of birds form Newfoundland and Belfast which are similar wing tips pattern to the Brid bay bird. I think the Weir et..al. article quoted above is the most helpful guides and concurs at least with my field experience: that Thayer’s and Iceland (glaucoides) were once separate entities and some introgression of thayeri genes has produced a dark winged Iceland Gull (kumlieni) with the melanin increasingly heading east through the glaucoides population resulting in increasing records in Greenland and NW Europe of ‘kumlieni’ (most diluted at eastern edge?). The core population of Thayer’s Gull in the west seems relatively stable and unaffected…

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