Herring Gull (argentatus & argenteus)
(last update: February 11, 2013)
Herring Gull 4CY, July 09 2013, Katwijk, the Netherlands.
This individual probably best left un-aged, as key-features are missing here due to moult. 4CY birds normally aged by sub-terminal pattern on central primaries: P5-P6 with clear cut blackish band and inner primaries adult-like grey. P5 just visible in right wing, suggesting such a clear-cut sub-terminal band, but P5 missing in left wing and P6 in left wing without obvious blackish pattern, in fact hard to tell apart from 2nd gen P6 with diffuse darker brown outerweb. Still, old P5 and pattern on old secondaries favour 4CY bird.
Secondaries and tail still old third generation; secondaries with large white tips and limited brown in the grey centre (sometimes only dark shaft streak) or limited vermiculation (often faint brown wash over outermost - first replaced- feathers), tail sometimes all white but often with some blackish lines or spots. Active moult in primaries (complete moult in summer months): P2/P5. No obvious mirror on P10.
