© A. R. Dean

An adult or 4W Caspian Gull photographed late afternoon in the gull roost at Coton Lakes, Warwickshire. An attractive and delicate example, probably a female. The first photo shows the general appearance and configuration: very white head offset well against smooth, deep grey upperparts (which are slightly less dark than most Yellow-legged Gulls);  slender build which is attenuated for and aft;  slim, parallel-sided bill, with indistinct gonys and rather pointed tip;  relatively long neck and small head but latter with loral feathering extending forward to create a somewhat 'snouted' appearance (enhanced by bill-shape). The base of the bill is rather olive-yellow, less rich than in most other large gulls, while the eye is beady and very dark, almost black. The distinctive head-profile is lost in the second photo, as the head is turning towards the camera, which has also lead to slight blurring of the outline. However, this image shows well the pattern of the outermost primary (p10) on the far wing. Note the extensive white tip and pale base to the inner web, which extends well forward;  the resulting pattern comprises a black lozenge  within a whitish field. A black subterminal band to the bill is common in adults in winter but its prominence on this individual - together with the merest trace of red in the bill and the blackish flecks at the extreme tip of p10 -  suggest that this bird is perhaps in its 4th winter rather than a full adult. The lower photos show enlargements of the iris and primary details.