Yellow-legged Gull - Larus michahellis

(last update: October 08 2013)

Delfín González
Gabriel Martín
Antonio Gutierrez
Amir Ben Dov
Mars Muusse

Yellow-legged Gull michahellis 2CY, March 17 2003, Boulogne-sur-Mer, France (50.42N,01.34E).

2CY michahellis Yellow-legged Gull with a 2CY argenteus Herring Gull. Note the shape of forehead, crown, strong breast and advanced moult in this 2CY michahellis, with second generation under-parts and moulted wing-coverts and tertials. This 2CY Herring Gull still shows juvenile scapulars in the lowest row and a complete juvenile wing and tertials. The michahellis has replaced the upper two tertials, the two inner greater coverts, some inner and central median coverts, about five lower lesser coverts and some lesser coverts. This individual nicely demonstrates that the exact sequence is very hard to detect by March as the juvenile wing-coverts are very abraded and bleached and the second generation wing-coverts required in an early stage (July-August) are very hard to separate from old juvenile feathers. The recently replaced wing-coverts still have a greyish hue. The tail-feathers and flight-feathers are still juvenile.
Fresh scapulars with a broad pale tip and grey hue can be found in the lowest row of scapulars and in the lower upper scapulars. Some lower upper scapulars are missing. The grey hued upper scapulars are recently moulted third generation feathers. In 2CY michahellis it's common to find birds starting to replace upper scapulars to third generation feathers, while the rear lowest scapulars have only very recently been replaced for second generation feathers. By this stage, this individual shows first generation feathers (remiges, rectrices, most outer wing-coverts), second generation feathers (the head, body, most scapulars and some inner wing-coverts) and at the same time third generation feathers (a few lower upper scapulars).
Note that in most 2CY individuals of this age-class the head and neck are by no way pure white, with delicate dark streaking concentrated around the eye and extending on the nape. In the hind-neck, 2CY michahellis often shows a boldly streaked neck-collar. The dark bill starts to turn paler at the base by February.