© A. R. Dean

Another first-winter Caspian Gull photographed in fading light in the gull roost at Coton Lakes, Warwickshire. The upper photo shows well the 'four colour zone' appearance of 1W Caspian Gull: white head, grey in the mantle and scapulars, brown on coverts and black wing-point. Note also:

• the characteristic profile to head and bill (shown to best effect in the smaller, lower photo, which is more directly in profile);

• very long primary projection;

• relatively clean, whitish forehead and throat;

• prominent streaking on lower, rear of neck, creating a shawl;

• grey base to mantle and scapular feathers, with neat internal anchor marks on scapulars, especially well-defined on rear scapulars;

• uniform brown base to greater coverts, forming dark band between pale tips of greater and median coverts;

• solid blackish-brown base to tertials with neat white 'thumbnails' at tips.