Herring Gull (argentatus & argenteus)

(last update: February 11, 2013)

Herring Gull 4CY, July 09 2013, Katwijk, the Netherlands.

Aged by sub-terminal pattern on central primaries: P5-P6 with clear cut blackish band and inner primaries adult-like grey.
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): small moult gap P2/P5. Note obvious mirror on P10.