2cy Yellow-legged Gull, Warks, July 2006

A second calendar year Yellow-legged Gull, moulting into 2W plumage. Individuals in this plumage can be quite easily over-looked but careful analysis of plumage (and to some extent moult) provides a number of clues. In the three photos note:

Robust but neat proportions, with powerful, deep bill. In relaxed posture (first photo), head-shape strong, with rather flat crown and vertical nape. Large individuals such as this (probably males) can have something of the demeanour of Great Black-backed Gull, enhanced by pale head and dark bill (photo 3 shows two YLGs, the 2cy alongside an adult).
Rather strongly contrasted plumage compared with Herring Gull of comparable age.
Relatively white ground colour to head, strongly contrasting with blackish bill (with yellowish tip). By this age, Herring Gull normally shows duller head and pale base to bill.
Fine head streaking, becoming denser and blotchier towards base of hind-neck.
Dusky patch around eye, highlighting pale 'eyelids'.
Second generation tertials with pale tip and pale sub-terminal band but solid dark bases (pale edges confined to terminal part of feathers). Herring Gull has more-variegated tertials, with more-extensive pale markings internally and along fringes, often creating an 'oak-leaf' pattern.
Coverts second-generation (and some greater coverts already dropped), patterned with strong cross-bars, many in the form of 'double anchors'.
New, third-generation feathers appearing in mantle and scapulars are plain slate grey (darker than argenteus Herring Gull, paler than LBB and comparable with darker examples of nominate argentatus Herring Gull).
In photos 1 and 3, two pale-tipped second-generation primary tips are emerging past the tertials; the central primaries have been dropped; and the outermost are old and faded first-generation. This state of moult in early July, while not outside the range of Herring Gull, is more compatible with Yellow-legged Gull.

Acknowledgement: I am very grateful to Dick Newell for discussion of the characters of this individual.

Yellow-legged Gull Larus michahellis

2cy ('first summer'), July 5th 2006, Warks