Herring Gull (argentatus & argenteus)

(last update: February 11, 2013)

Herring Gull (argenteus) NLA 5.361.238 5CY & 16CY, March 2004 & October 2015, Brouwersdam, the Netherlands.

Herring Gull ringed as pullus on July 02 2000 at 3 Oesterdam, Tholen, Zeeland, Nederland (51° 30' 22 N, 4° 11' 4 E).

Recoveries: .
23-10-2015 Brouwersdam, Ellemeet, Schouwen-Duiveland, Zeeland, Nederland (51° 44' 50 N, 3° 49' 26 E). Picture.
19-02-2013 Brouwersdam.
12-02-2013 Brouwersdam.
16-11-2012 Brouwersdam.
22-10-2012 Brouwersdam.
30-09-2012 Brouwersdam.
13-02-2011 Brouwersdam.
11-01-2011 Brouwersdam.
31-12-2010 Brouwersdam.
24-08-2010 Brouwersdam.
10-03-2004 Brouwersdam.
10-04-2002 Brouwersdam.
02-07-2000 3 Oesterdam, Tholen, Zeeland, Nederland (51° 30' 22 N, 4° 11' 4 E).

below: Herring Gull (argenteus) NLA 5.361.238 16CY, October 23 2015, Brouwersdam, the Netherlands.

Bird in complete moult: P8 fully grown.

below: Herring Gull (argenteus) NLA 5.361.238 5CY, March 10 2004, Brouwersdam, the Netherlands.

The head is complete white, all winter streaking absent. Adult argenteus may already return to the colonies in January-February, maybe depending on the weather conditions (mild winters north to 53° latitude along the coast of the North Sea). It's unknown in what way and to what extend weather conditions influence body feather moult, but from January onwards, adults may appear with snow-white heads. From late January and certainly from the first week of February, males start defending territories on the roofs of the industrial complexes in the harbour of IJmuiden and in the colonies of the Maasvlakte, near Rotterdam. 
From the second week of February onwards, adult argenteus from the Netherlands are in active moult on the head. This is often obvious in the feathers around the eye, which are shed by the second week of February, leaving a naked ring around the eye (visible at close range). Note the orange orbital ring and the limited black on the bill (possible in full adult birds).