The Caspian Gull below shows a good set of features, Long sickly flesh coloured legs; long parallel sided dingy yellow bill (dark marks on bill suggest immaturity); dark forward set eyes; small headed; long winged and the pattern of black and white on the underside of the longest primary feather (P10) is typical of a sub-adult Caspian Gull. The black subterminal mark on the bill and the upper wing pattern appeared slightly immature, so it is probably a fourth-winter. The primary coverts still have some black visible, which is another good indicator of its immaturity.
It is not so easy to see, but a white tongue cuts under the black of P10. That said there is slightly more black than classic individuals show, but its still within normal variation especially if my ageing is correct. It can be seen better on some photos I took of it, but this one shows a nice profile.
The shape of gulls can alter in a split second. One minute this Caspian Gull looked elegant and small headed and the next it could look hunched and larger headed.
|Sub-adult Caspian Gull|
|Sub-adult Caspian Gull - note pattern on underside of longest primary feather|
As well as the one above, I saw a first and second-winter plus a hybrid Caspian x Herring Gull. The first-winter was a female and really dainty.
|First-winter Female Caspian Gull|
|Presumed hybrid Caspian x Herring Gull|