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Caspian Gull features? (1 Viewer)

Andrew

wibble wibble
There is no text in my guides on Caspian Gull. Is it a race of Herring Gull?

I checked some pictures and the common thing seems to be a cleaner head. Is this the right track of thought?

What should I look for when trying to pick out a Caspian Gull?
 
Hi Andrew,

I see you're planning for your trip to the Midlands! In the Collins Guide, Caspian Gull isn't properly mentioned or illustrated but if you look under the entry for Yellow-legged Gull, there's a bit about the race cachinnans and this is Caspian Gull. A recent thread about a bird I saw in Northamptonshire might be helpful:

http://www.birdforum.net/showthread.php?t=11786

I think there was another thread a few months back in which Spud mentioned a few good points and gave links to various websites with pictures.

I picked up most of what I know about them on the web, as there's virtually nothing in books. There's a good accessible article on Birdguides called 'What is a Caspian Gull', which I recommend. The best article is from BB a few years ago (97?) by Martin Garner.

From what I know the key things to look for are bill shape (can be quite distinctive - parallel side, quite pointed at the tip and long), dark eye, long, slender dull yellowish legs (usually) and wing tip pattern (quite complex but more white and less black than Yellow-legged). Apparently they have really wierd donkey like call as well. The overall impression is almost like a giant Common Gull - they're 'gentle giants'.
 
Hi Andrew(both of you!),
Would agree with what Fifebirder says above,but would add that adult birds can sometimes show an odd greyish-flesh leg colour in winter,and 1st-w birds etc also have pink legs(though a different pink to that shown by the 'ordinary' large gulls).
The call is on the Calls of Eastern Vagrants CD,and is quite distinctive,though I'm not sure how useful this would be amongst hundreds of other gulls?;)
1st-w birds are also quite obvious,at least as large gulls of that age group go,and can be identified by a combination of structure,greater covert pattern(tends to have dark greater coverts with a pale tip,producing a pale 'wingbar'.Sometimes there is a second 'wingbar' formed by pale tips to the median coverts),head streaking(while even michahellis Yellow-legged tends to have some streaking on the face etc in 1st-w,Caspian is much whiter-headed,with streaking on the nape contrasting with the white head),underwing(almost white,with no contrastingly dark area on the underwing coverts as in most other large gulls) etc.
There are lots of good gull websites out there,and I can recommend the literature suggested by Fifebirder above,and also an article in Birding World back around Feb.00(?),not to forget Lars Jonsson's masterly dissertion on the ID of Yellow-legged and Caspian in Alula back in '98.
Harry H
 
Try this link - i found it extremely helpful!

http://www.surfbirds.com/ID Articles/casp.html

Key pointers are Long legged appearance, attenuated rear end, small head with a long sloping forehead giving onto a long, relatively slender, parallel sided bill - plumage differences vary with age but I would stress that (other than primary pattern) no single feature is really characteristic - more a combination of factors.

I`ll be honest though, in my opinion a Gull roost is a very difficult way of getting to grips with Caspian Gull particularly for your first time - the birds are distant, light is poor and they are usually packed in with hundreds if not thousands of other similar birds - i`d try and get to grips with them under circumstances which allow closer observation of the more subtle features and prolonged observation so posture and structure differences can be properly assessed.

I`m sure a proper Gull expert will help you more - i`ve much more experience of dismissing Yellow-legged Gull than "clinching" Caspian Gulls.

Good luck for the weekend though! Whilst you`re heading up this way we`ll probably be crossing over - Saturday or Sunday I really fancy that Penduline Tit!!!
 
In case you get one of ours (mongolicus), I look for the rounded, whiter head and the paler mantle (than our 'Herring', vegae)in the winter adult. The first winter birds appear to differ from Harry's point in that the visible ends of the greater coverts are mostly pale-- the whole back in fact is paler-- while vegae's show as a darker 'bar' with light tips.
 
I'd agree with Jason on gull roosts. I think they're quite hard places to learn. It's better if you can find somewhere that gulls congregate during the day where you can hopefully have a much better view. If you go anywhere near Northampton, there's been a regular adult Caspian Gull at Clifford Hill Gravel Pits recently. I saw it a few times and it just seemed to sit about the main lake all day. The only problem was that it was quite often the only big gull there, so there wasn't much to compare it to.
 
Thank you all for the suggestions for learning material. I shall print them all off and study them.

Certainly will be a taxing proposition to find one. Hopefully one of the regulars at the sites will point them out to us to help us learn the features. There is one in London on a lampost and I could try going for that one if I plan the train connections.
 
Andrew

The unstreaked white heads of Caspian and Yellow-legged are more obvious earlier in the autumn or early winter when Herring and LBB have more or less heavily streaked heads.

Argenteus Herring Gulls can now show unstreaked heads and the others will get whiter over the next few weeks.

The best viewing is often where the birds have found an area near to their feeding spots where they can have a 'wash and brush-up' and general socialisation.

Whilst preening there is often a chance to check out the wing formula of a suspect bird - the outermost primary (P10) is diagnostic if seen well but Caspian is more easily seperated from YLG by this method than from Herring which has a similar pattern - it's the longer white tip and thus narrower black area between the tip and the 'finger' that you need to home in on. (Check some of the links above for illustrations of precisely what you're looking for)
 
ID of Caspian would take up much more space than I'm prepared to write and you're prepared to read!

Perhaps best ref at moment is Martin Garner's article in BB 1997 vols 1 and 2
 
I read all the info and literature but when we got to Chasewater and saw thousands of gulls on the evening roost I threw the idea of finding it out the window. I did however have some consolation as whilst looking for anything unusual I found a 1st winter Glaucous Gull which was an excellent lifer for me. That follwed some lifer Waxwings in the morning.
 
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