Yellow-legged Gull - Larus michahellis
(last update: October 08 2013)
Larus michahellis - adult December
This website deals with the Yellow-legged Gull taxon michahellis, which is a common migrant from July to December in NW Europe. After extensive expansion of the breeding population during the last three decades, it nowadays can be found breeding in Belgium, the Netherlands and Britain in mixed couples with both Herring Gull (argenteus) and Lesser Black-backed Gull (graellsii). There are subtle differences between the populations from the Mediterranean, Atlantic coast of Portugal and Morocco and from the islands in the Atlantic. Most pronounced differences can be found in the taxon atlantis, now regarded as full species by some authors and birds along the Atlantic coast of the Iberian peninsular: lusitanius. Both atlantis and lusitanius are treated in their own sections on this website.
Moult of remiges and rectrices
Average adult michahellis have
finished the complete and partial wing-covert moult by the end of October and moult is
normally suspended throughout November and December. A few
birds which were mouling the inner median or inner greater coverts may
just finish this moult by early November. By the end of December, most birds
show wear in the coverts again, most noticeable at the inner coverts.
Moult in the remiges and rectrices
Early November it's still possible to find adults with P10 not fully-grown; in these birds primary P10 has to grow an inch or two. Rectrices and secondary moult was finished by the end of October.
Moult of the body feathers
The body feather moult was finished in September. As can be seen in the image from November, the feathers on the head may show obvious streaks, although this bird from Britain is extraordinary in the amount of streaking. Normally adult michahellis start to turn completely "white-headed" by December.
In full adult michahellis, the colour of the legs hardly turns paler in winter. There may be some dark markings on the cutting edge of the bill or on the gonydeal angle in otherwise full adult birds.
|Yellow-legged Gull michahellis 19CY-22CY C 53597 Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.|
|Yellow-legged Gull michahellis 6CY SH49 PA23107 December 07 2012, Witoszowka, Swidnica, Dolnoslaskie, Poland (50.49 N 16.28 E). Picture: M. Dabek.|
|Yellow-legged Gull michahellisHES M013922 4CY-5CY, October 2013 & December 2014, Barneveld, the Netherlands. Picture: Maarten van Kleinwee & Merijn Loeve.|
|Yellow-legged Gull lusitanius 2CY, 7CY & 8CY AJ1N 2006, 2011 & 2012, Gijón, Spain.|
|Yellow-legged Gull lusitanius 16CY CLV December 29 2012, Nazaré, Leiria, Portugal. Picture: Angel Sánchez.|
|Yellow-legged Gull lusitanius adult FGB December 29 2012, Nazaré, Leiria, Portugal. Picture: Angel Sánchez.|
|Yellow-legged Gull lusitanius ZH4M adult, December 08 2011, San Cibrao, Spain. Picture: Antonio Gutierrez.|
|Yellow-legged Gull lusitanius ZM62 adult, December 08 2011, San Cibrao, Spain. Picture: Antonio Gutierrez.|
|Yellow-legged Gull lusitanius ZMT1 adult, December 08 2011, San Cibrao, Spain. Picture: Antonio Gutierrez.|
|Yellow-legged Gull lusitanius ZNB0 adult, December 08 2011, San Cibrao, Spain. Picture: Antonio Gutierrez.|
|Yellow-legged Gull lusitanius adult F123 December 29 2012, Nazaré, Leiria, Portugal. Picture: Angel Sánchez.|
|Yellow-legged Gull michahellis adult, December 20 2014, Sardinia, Italy.|
|Yellow-legged Gull michahellis adult, December 05 2009, Italy. Picture: Giorgio Bonomo.|