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 071Z February - May 2003, Etaples / Boulogne-sur-Mer, France (50.31N,01.39E).

Bird ringed Lagune des Impériaux, Besson / Bouche-du-Rhone, France (43.29N 04.27E).

readings of michahellis 071Z. Bird ringed Lagune des Impériaux, Besson / Bouche-du-Rhone, France (43.29N 04.27E).
date location observer
24.05.2002 Besson, France (43.29N 04.27E). ringed by ringer
24-26.10.2002 Etaples, France (50.31N 01.39E) Bert-Jan Luijendijk, Mars & Theo Muusse
08.02.2003 Etaples, France (50.31N 01.39E) Mars Muusse
16-18.03.2003 Etaples, France (50.31N 01.39E) Mars & Theo Muusse
13.04.2003 Etaples, France (50.31N 01.39E) Jean-Michel Sauvage
29.04-02.05.2003 Etaples, France (50.31N 01.39E) Bert-Jan Luijendijk, Mars & Theo Muusse

This individual was seen at the same location in NW France on October 24 2002. The moult score by then was almost exactly the same as in February. The only progress since October has been in the median coverts: by October two feathers were replaced, in February four feathers are second generation. This nicely illustrates the idea that partial autumn moult (post-juvenile moult) is largely finished by late October. (see also image 6058-59).

below: michahellis 2CY 071Z February 08 2003, Etaples / Boulogne-sur-Mer, France (50.31N,01.39E).

Typical 2CY michahellis with the tertials and all rectrices still juvenile. It has moulted the head, neck, breast, flanks and belly to second generation. It also included some wing-coverts in this moult: In the left wing, greater coverts #10, median coverts #1,4,5 and #7, lower lesser coverts #1, #3-5, #7-9 and six lesser coverts are second generation as well. The other wing-coverts are still juvenile.
The lowest row of lower scapulars are fresh second generation feathers with a grey base and neat fringes on the last replaced feathers, well visible in the rear feathers. Several upper scapulars have been replaced recently for grey third generation feather. In 2CY michahellis it's common to find birds continuing to replace upper scapulars to third generation feathers, while the rear lowest scapulars have only very recently been replaced for second generation feathers. White 071Z in February shows first generation remiges, rectrices and most wing-coverts, it shows second generation head, body, most scapulars and some inner wing-coverts and at the same time third generation lower upper scapulars (about four).
Note that the head and neck are by no way pure white, with dark streaking concentrated around the eye which extends on the nape and a bolder streaked neck-collar. The dark bill starts to turn paler at the base.

February 08 2003

The image below shows 071Z by March. There is not much progress regarding moult, except in the upper region of the scapulars and the mantle.

March 17 2003

071Z was still present from late April and in the first week of May 2003. By late-April the primary moult has started obviously as the innermost flight-feathers have been dropped. In the second image the primary moult score can be seen (PMS: 8), with P1 fully grown and P2-P4 missing.
As is the case in many 2CY michahellis by early May, this bird looks shabby, with obvious gaps in the median and greater wing-covert rows. The feathers which were included in the post-juvenile moult are normally left out of the complete moult in spring until July. The exact moult sequence often is hard to obtain, as the old second generation wing-coverts are hardly recognized between the old juvenile feathers. Here, greater covert #1 is new, fully grown, #2 is growing and all other greater coverts are still juvenile, except greater covert #10, which was included in the partial moult.
Median covert #1 is still old second generation, #2-3 are missing, #4-5 are old second generation and from #6 outwards, the median coverts are missing, the new tips of the outer feathers already visible. One single outer media covert is still old. It seems the second generation medians are left out of the first stage of the complete moult in the wing-coverts, as can also be seen in Sempach 885629.
Lower lesser coverts #1, #3-5 7 #7-9 were included in the post-juvenile moult. The exact sequence in May is difficult to interpret, but at least four lower lessers are still old second generation (jumping sequence) by early-May, two central lower lessers seem to be juvenile and the other lower lessers are missing.
About four lesser coverts are old second generation and more than five lessers are missing.
Irregular moult sequences are not found in the tertials, as in most birds replacement in the tertials follows the ordinary sequence, from tertial #1 downwards. 071Z has tertial #1 missing and #2-6 still juvenile.
Moult in the scapulars is pretty advanced, with 50-75% grey third generation: almost all upper scapulars have been replaced (75-99%) and 25-50% of the lower scapulars have been replaced for grey feathers with a black shaft-streak. Two lower scapulars in the lowest row are missing.
The orbital ring is pale brown, caramel coloured.

May 01 2003

May 02 2003