Steppe Gull barabensis in South Korea - Comments

Neil Davidson (May 15, 2005):

Thanks for letting me see your draft paper which I enjoyed reading. It highlights some of the gaps in our understanding of Asian gulls, perhaps increasing observer interest in South Korea will provide a valuable insight into over-wintering and gull movement on the continental mainland. Until now the better-watched Hong Kong area seems to be the only window onto an otherwise little studied coastline…

Your images of putative barabensis, as well as looking quite distinctive in themselves also look different from other typical taxa of the region and also share persuasive consistencies as a group…

  • Figure 1 of your paper looks a very convincing bird. The total lack of streaks on the lower hind-neck suggest it has completed it’s head and body moult into summer plumage by 4th March, which seems more than unlikely for a northern group taxon, and the tatty-looking coverts and tertials also seem appropriate for a southern breeding, earlier moulting taxon, though the affect of immaturity on moult timing has to be taken into account. A lot of adult mongolicus have more worn scapulars and wing-coverts at this time. The dark ’piggy-eyed’ appearance looks interesting, even if it looks more suggestive of a western cachinnans than a barabensis, and single images can be misleading, but on the whole this bird ’feels right’, it’s certainly very different to any of the taxa we recognize as part of our winter avifauna.

  • Figure 4, though not exhibiting a ’perfect’ Steppe Gull bill pattern (perhaps sub-adult?) is also a strong contender, it’s an excellent shot, it would be nice to see it from other angles. It would also be helpful to see some spread-wing shots.

  • Unfortunately the quality of the images in Figures 17-18 isn’t so good. At first glance they look superficially very similar to some of the birds I have seen (in Osaka), so if I only had the images to go on I’d be doubtful about them. That’s not to say they aren’t good candidates for barabensis, especially in the light of images 1 & 4, but that I’m sceptical about ’my birds’, and these images alone don’t show enough detail to totally convince me beyond any doubt that they and the ’bandbills’ are different. However structurally these birds (Figs 17-18) have a ’better’ head-shape than any of the ’bandbills’ here, and more signifiantly look far cleaner-headed. Though there is a suggestion of streaking on the neck but it may just be the image quality. Figure 18 also shows a long mirror with a narrow black band on P10 which Martin Reid seems to consider more a feature of cachinnans but looking at Steppe Gull photographs from different sources (including "Gulls") it’s obvious that this feature is subject to a degree of variation which we expect in large gulls.

As I said earlier I’d like to see a classic barabensis-type to be happy to claim it, and I think such conservatism results in the boundaries of what is acceptable in any rare taxon only gradually being expanded because observers tend to be cautious about including marginal individuals when assessing infrequently seen or little known taxa; either or both terms could be applied to most gulls breeding between eastern Europe and the Pacific littoral, without throwing extralimital complications into the mix….

Dave Sargeant (June 3rd – 6th, 2005):

  • On Figure 1: “Typical” barabensis.

  • On Figure 4: ”No comment here. I wouldn’t like to call this a barabensis from this photo.”

  • On Figures 5 and 6: “Note the longer bill and head-shape in front bird - typical cachinnans.”

  • On Figure 9: a taimyrensis: ”Never seen one like this in Middle East”.

“The adults of the various types are quite easy to separate (I think) based mainly on structure. I think Dick Newell’s photos of barabensis (Click here) are very representative.”

In response to specific questions from Nial Moores:

NM asked: Are barabensis obviously shorter-legged, and rounder -headed than heuglini and cachinnnans?

DS: Shorter legged I had not noticed. They definitely have a rounder "cuter" head. Separation from (presumed) heuglini is easy, as the heuglini here are larger, with relatively more massive heads and bills - they look ferocious. Separation from cachinnans is more difficult and some birds I wouldn’t like to say. However, the main features I note in a "good" barabensis are:

  1. very white plumage (seem to shine in good light)

  2. very yellow legs. (Legs of cachinnans are often yellow, but not so bright.)

  3. rounded head

  4. very limited mirror in wing

NM: In adults (non-breeding and/or breeding plumage) is the variation significant in bill pattern? Leg colour? Eye-colour?

DS: I wouldn’t like to say. Bill structure is similar in barabensis and cachinnans to my eye.

NM: Do some heuglini where you are show dark bill markings and pale bill tips as adults in winter?

DS: Don’t know - I haven’t studied them well.

Martin Garner (June 4th, 2005):

The photos you sent (Figures 7 and 8) look like classic barabensis to me. I must say I do not know the east Asian gulls to differentiate, but your bird is perfect including number of black marked primaries (7 to 8) the bill shape, the rather short squat look to legs is common to many, the overall upper part tone (or at least the feel of it): everything really. Moult would be helpful I guess. This bird is fully winged: barabensis reach a full new set of primaries in my experience by Jan/ Feb, earlier than heuglini, but later than cachinnans.