• BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

    Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Caspian Gull UK (1 Viewer)

GMS

Well-known member
Another 1st Winter Caspian Gull I think. Digiscoped at range and in heavy rain/wind. Looking at my pics the bird looks very different, depending on angle etc. Quite heavily marked on the back and a rather strong bill
 

Attachments

  • 20210130_121542.mp4
    15.1 MB · Views: 0
  • 20210130_121532.mp4
    9.8 MB · Views: 0
  • 20210130_120944.mp4
    10.6 MB · Views: 0

aeshna5

Well-known member
For me the bird in the first image looks exactly how I would expect a 1st winter Caspian Gull to look like & many photos of these have posted on the Dungeness Observatory daily updates in recent months.
 

GMS

Well-known member
Thank you. Still from video now attached, with bird thinking about picking up the golf ball again. Always difficult to judge from one photo, especially as it's moving but it just looks a bit stocky and large billed to me, even though other plumage features, incl. Head, neck, coverts pattern, wing pattern, underwing etc. look fine to me.
 

Attachments

  • 20210130_173727.jpg
    20210130_173727.jpg
    120.3 KB · Views: 21

HH75

Well-known member
Ireland
Hi GMS,
To me, this is quite a tricky bird. It may well be a Caspian Gull, a less than typical one in some respects but variation occurs. However, given the existence of F1 and F2 hybrids involving Herring Gull genetic input on one hand, and variation in Yellow-legged Gull on the other, I don't know how confident I would be about this one purely from the evidence available.
To me, the tertial pattern seems to show a pale fringe to the outer webs back along a substantial portion of the feather's length. This pattern is something that I associate more with 1st cycle Yellow-legged or Lesser Black-backed Gulls, but, of course, no one single feature is diagnostic in these matters. The nature of the head pattern, with a heavily streaked nape contrasting with a whiter head, also seems interesting. Caspian Gull of this age class does, of course, have nape streaking, but the nature of the streaking here, almost being more in the form of solid blotching, reminds me more of Yellow-legged. The 2nd generation scapulars have rather large dark centres, which some Caspians can show, but this also would arguably be a better fit for a Yellow-legged or else be indicative of Herring Gull genetic input. I'd maybe feel easier about this as a Yellow-legged if it had some 2nd generation coverts or innermost tertials, but not all birds attain these during the partial post-juvenile moult, and, while the greater coverts look as though they may have been quite uniformly brown when fresh (i.e. not with the innermost coverts more notched/barred), this is difficult to assess.
Of course, living in Ireland, where Caspian Gull remains rare and not quite annual, I admit that I might look more critically at less than 'perfect' candidates than if I lived within their core range, so I wouldn't necessarily let my scepticism put you off too much!
Any stills showing the spread wing and/or underwing patterns better? And how pale did the underwing seem in life?
Regards,
Harry
 

GMS

Well-known member
Thanks Harry. Some additional stills attached. No side-on underwing shots and the ones attached are not of great quality. However underwing nice and pale in real life.
 

Attachments

  • 20210130_174227.jpg
    20210130_174227.jpg
    101.8 KB · Views: 16
  • 20210131_182544.jpg
    20210131_182544.jpg
    81.3 KB · Views: 16
  • 20210131_182433.jpg
    20210131_182433.jpg
    87.6 KB · Views: 13
  • 20210130_175024.jpg
    20210130_175024.jpg
    82.9 KB · Views: 16

Users who are viewing this thread

Top