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, April 30 2003, Etaples, NW France (50.42N,1.34E).

2CY michahellis from late-April. This bird nicely demonstrates the extend of the partial post-juvenile moult (first pre-basic moult). Last autumn, most inner wing-coverts were included in this post-juvenile moult and they appear as old second generation feathers by late-April. 
The three upper tertials are old second generation, while the lower three tertials are still juvenile. 
The inner four greater coverts are old second generation, while the central and outer greater coverts are still juvenile.
About nine inner median coverts are old second generation, while the outer median coverts are still juvenile. Median covert #5 is missing and #6 has been replaced recently, still showing a broad white fringe.
The inner eleven lower lesser coverts are old second generation, while the outer lower lesser coverts are still juvenile. In the inner-half of the row, one feather is still juvenile and one feather is growing.
About eleven lesser coverts were included in the post-juvenile moult. 
In the lower upper scapulars, fresh third generation scapulars have been moulted, which show a grey base and an ill-defined anchor shape. The most recently replaced feathers appear all grey with only an accentuated dark shaft-streak.