andy,
there is a pale inner primary window, you can see it in the underwing shots. it would be visible on upperwing if it had its wings more spread.
while primaries and coverts in the pic with visible upper wing appear on the dark side for for cachinnans, all visible (greater) coverts are 1st generation - at this time of year (to the end of february), most heuglini have moulted their coverts due to their advanced moult strategy. heuglini is very rare in central europe while cachinnans is rel. common. (last issue not serving as an argument for the id of this bird but it's always good to think realistic first).
cheers,
Hi Lou,
I'm sure you are probably right and the chances are that this bird is a cachinnans. It would certainly be useful if more images were available of Heuglin's taken in Feb/Mar though.
I stil think that this bird shows darker inner primaries than should be expected of a (typical) Cachinnans. The rounded tips of the inner primaries can be seen in the new images so therefore we can see a lot of the inner webs and they look dark to me. Compare to the birds in the this link:
http://www.kentos.org.uk/North West Kent/CaspianGull6.htm
and photo attached (taken on 9-12-7 by Barry Wright).
Both birds show an obvious 'venetian blind' effect.
Note also how much more chocolate brown the greater coverts are on these birds compared to the darker greater coverts of the subject bird.
Also note this bird:
http://www.gull-research.org/heuglini-id/heuglini7.html
This bird, photographed in June, has not moulted most of its greater coverts and those that have been replaced may have been replaced much later than March. Also note how dark the older greater coverts are and compare to the subject bird above. Identical? Well, very close at least IMO. Note also how similar the inner primaries on both the Russian Heuglin's and the German bird are. I also feel that Heuglins may show a larger black eye than Caspian and comparison of the Russian bird to the German bird seems to help support this. Also note the larger, thicker bill of Heuglin's compared to Caspian and note the large, thick bill of the German bird.
And have a look at this one:
http://www.gull-research.org/heuglini-id/heuglini12.html
OK, I could be well off the mark with all of the points I've made above, but then who can identify Heuglin's Gull in 2cy plumage in March (fishing line goes out with bait attached.....
)?
To sum up, the German bird seems to show more characters of Heuglin's than Cachinnans. It would be useful to see images of this bird from above to see how advanced the upperpart moult is, perhaps.
Cheers,
Andy.