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 365D July 2001, September 2002 & August 2003, Etaples, France (50.42N,1.34E).

Michahellis ringed white right 365D, ringed as pullus on June 03 1999, Porquerolles island near Hyères, France (43°00N, 06°21E) by Eric Vidal.

This bird was reported several times in the harbour of Etaples, near Boulogne-sur-Mer:
1999: (1CY) on October 09 by Roland-Jan Buijs.
2000: (2CY) on August 13, September 08 & 17, October 01 & 08 by Jean-Michel Sauvage.
2001: (3CY) June 16, 20 & 23 by JM Sauvage; July 27, 28 & 30 by Bert-Jan Luijendijk and Mars Muusse.
2003: (5CY) August 08-12 by Ruud Altenburg and Mars Muusse.

Contact for information on this project:
Eric Vidal:
Maitre de Conferences (Lecturer)
Institut Mediterraneen d'Ecologie et de Paleoecologie (IMEP-CNRS, UMR 6116),
Faculté des Sciences et Techniques de Saint Jerome
case 461, 13397 MARSEILLE Cedex 20, FRANCE.
Tel : (33) 4 91 28 27 44 / Fax (33) 4 91 28 80 51.

image below: 365D michahellis 3CY, July 27 2001, Etaples, France.

Primary moult score on July 27 2001: P5 is almost full grown, P9-P10 are old. This bird is moulting tail-feathers and tertials: the upper 3 tertials are new, #4 is growing. The greater covert moult stage: #1-2 new, #3-4 old, #5-15 missing, #16-> growing. The median covert moult: #1-3 new, #4 missing, #5 old, #6-> new. Active moult is in progress in the lower lesser, the lesser coverts and scapulars. There is still some black on the upper mandible  and the legs are  pink-yellow.

Primary moult score in 3CY Larus michahellis, Etaples, NW France on June 28 2003 (09:00 h, low tide).
. P2 fg P3 fg P4 fg P5 fg ? fg n:
P5-P10 1 - - - 6 7
P6-P10 - 3 - - 34 37
P7-P10 - 4 3 1 27 35
P8-P10 - - 1 2 2 5
n: 1 7 4 3 69 84
n = 84; m old P = 4.5; SD old P = 0.73.
Group: 3x 3CY michahellis not scored; total michahellis present: 300+.
P6-P10 = P6-P10 are still old and present.
? fg = fully grown not known. Often referring to sleeping birds with folded wings, so fully grown primary score most probably P6 or less.
fg = fully grown. In our field surveys, a primary is 'fully grown' when it exceeds the previous feather in the folded wing. Actually,  such 'fully grown' feathers may have to grow a little, but under field circumstances, it's very difficult to find out if the waxy sheath, which is the standard measurement for fully grown primaries, is still present. 
3CY identified on absence of P10 mirror & bare parts coloration.

image below: 365D michahellis 4CY, September 21 2002, Etaples, France.

Sub-adult Yellow-legged Gull with primary P7 fully grown. Note the diffuse bill-band and the pale yellow base of the bill, the rather pale yellow legs and the dark pigmented iris. In the bottom picture, the dark markings on the primary coverts are clearly visible. Note also the growing secondaries in this individual.

image below: 365D michahellis 5CY, August 09-11 2003, Etaples, France.

Summer 2003, 365D was seen again at the same location. There is still some limited black in the bill, but this is not uncommon in full adult birds. P9-P10 are still old, P6 is fully grown.