Great Black-backed Gull (Larus marinus)

(last update: October 12, 2011)

Coordinators:
Jean-Michel Sauvage (France)
Morten Helberg (Norway)
Nils Helge Lorentzen (Norway)
Mars Muusse (Netherlands)

Great Black-backed Gull adult September

By September, adult GBBG are still in active moult, most birds growing the central primaries and dropping. As can be seen in so many large white-headed gulls, approximately when P6 is growing, birds start moulting secondaries and rectrices. Of course the tertials (which in a way could be interpreted as inner "secondaries" as well) are included in the moult process much earlier in the season, but when P6 is growing, a new moult wave starts in the outermost secondary (S1), the feather next to P1. The first phase of the secondary moult progresses slowly, one feather at the time, but when the new outer secondaries are visible, a much larger moult gap soon appears in the central secondaries. At the same time, the moult wave that started in the upper tertials continues as well, and the two moult waves meet approximately at S16.

Rectrices (tail feathers) will be moulted in September as well, this process is centrifugal, starting ate the inner feathers and progressing outwards. The exact location of the last remaining old feather is difficult to interpret, but this is not necessarily R6 (the outermost feather). Leaving R5 as last old feather is a common startegy.

An indication of the primary moult of GBBG, and compared to YLG (michahellis) and HG (argentatus) is presented in the tables below:

Tables:

marinus adult PMS Boulogne-sur-Mer (roof) old vs new primaries.
September 21 2002, Boulogne-sur-Mer, NW France.
old vs new ?? p5 new p6 new p7 new
P4-P10 old 1 0 0 0
P7-P10 old 2 0 0 0
P8-P10 old 3 16 0 0
P9-P10 old 0 15 3 0
P10 old 0 4 37 0
0 old 0 0 0 1
n = 82
m old = 1,8 SD old = 1,08
m new = approx 5,4 SD new = approx 0,65

.

marinus age scored against fully grown new primaries, September 21 2002, Boulogne-sur-Mer, NW France (on the roof).
. p5 new p6 new p7 new p8 new p9 new p10 new m = n = SD =
2nd cy - - 2 6 2 - 8,0 10 0,67
3rd cy - - 7 1 - - 7,1 8 0,35
4th cy - 1 3 - - - 6,8 4 0,25
adult 35 40 - - - - 5,4 82 0,65

.

adult michahellis scores of fully grown new primaries: Etaples, NW France, September 21 2002. Sample and control sample.
new prims I - Sept 21 2002 II - Sept 21 2002
p7 34 58
p8 47 50
n: 81 108
m: 7.6 7.5
SD: 0.50 0.50

Notes:
All old primaries are shed by late September, except in three birds (2 in sample I, 1 in sample II, all with p7 new);
Due to the very similar plumage of some near-adult michahellis, it's not completely sure all scored birds are indeed fully adult. However, the time lag between these two age-classes is very limited and it's believed only few sub-adults are included at most.

.

adult michahellis fully grown new primaries, September 29 2001 Etaples
. p5 new p6 new p7 new p8 new p9 new p10 new m = n = SD =
morning - - 2 44 2 - 8.0 48 0.29
afternoon - - 13 95 11 - 8.0 119 0.45

.

michahellis age scored against fully grown new primaries, September 29 2001 Le Portel (morning score).
. p5 new p6 new p7 new p8 new p9 new p10 new m = n = SD =
2nd cy - - - - 1 6 9.9 7 -
3rd cy - - - 2 7 1 8.9 10 0.57
4th cy - - - 3 3 - 8.5 6 0.55
adult 1 - 4 20 3 - 7.9 28 0.76

.

michahellis age scored against fully grown new primaries, September 29 2001 Le Portel (on the roof).
p7 new p8 new p9 new p10 new m = n = SD =
2nd cy - - 5 12 9.9 17 -
3rd cy - 2 16 5 9.1 23 0.55
4th cy 4 8 3 - 7.9 15 0.70
adult 8 26 3 - 7.9 37 0.54

 

 

8011gbbg9158322.jpg (90352 bytes)Great Black-backed Gull (Larus marinus) J7MZ November 2007 & September 2013, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.

8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 6cy J7RH September 10 2011, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.

8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 6cy J9K5 September 24 2007, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 5cy J9RJ September 02 2010, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 9cy J90N September 17 2011, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull(Larus marinus) 7cy & 9cy JE4H September 2009 & 2011, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JH5R September 2007, August 2010 & September 2012, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 5cy JHX9 September 02 2010, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 6cy JL8C September 01 2010, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 9cy JP36 September 17 2010, Westkapelle, The Netherlands. Picture Ies Meulmeester.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 9cy JZ1K September 17 2011, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 5cy JZ2J September 24 2007, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
jzp7a.jpg (75884 bytes)Great Black-backed Gull (Larus marinus) 5cy JZP7 September 24 2004,  Scheveningen, the Netherlands.
Primary P6 is fully grown and P9-P10 still old.
1598.jpg (74227 bytes)Great Black-backed Gull JZ11 (Larus marinus) 8+cy, September 10 2011, Boulogne/Mer, France. Picture: J-M Sauvage.
1598.jpg (74227 bytes)Great Black-backed Gull (Larus marinus) 5cy JA112 2008, 2011 & 2012, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
1598.jpg (74227 bytes)Great Black-backed Gull JE165 (Larus marinus) 6+cy: August - September 2012, Boulogne/Mer, France. Picture: J-M Sauvage.
8011gbbg9158322.jpg (90352 bytes)Great Black-backed Gull (Larus marinus) 4CY-5CY JE446 2012 & 2013, Boulogne sur Mer, France.  Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull JH402 (Larus marinus) 4+cy: September 22 2011, Westkapelle, the Netherlands. Picture: M v Kleinwee.
8011gbbg9158322.jpg (90352 bytes)Great Black-backed Gull (Larus marinus) JHX9 / NOS 3005933 2010, 2012 & 2013, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
1598.jpg (74227 bytes)Great Black-backed Gull DKC 3063710 (Larus marinus) adult, September 30 2010, Boulogne/Mer, France. Picture: J-M Sauvage.
1598.jpg (74227 bytes)Great Black-backed Gull NOS 360820 (Larus marinus) 7cy, September 11 2011, Boulogne/Mer, France. Picture: J-M Sauvage.

2186nos367624.jpg (73256 bytes)Great Black-backed Gull NOS 367624 (Larus marinus) adult: September 18 2004, IJmuiden, the Netherlands (52.27N - 04.33E).
Primary P7 is fully grown while P10 still has to be shed.

2186nos367624.jpg (73256 bytes)Great Black-backed Gull (L. marinus) NOO OA13312 September 24 2006, IJmuiden, the Netherlands. Picture: Ruud Altenburg.

8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 5K3 adult, September 29 2010, Gloucester, MA. Picture: Joey Ciaramitaro.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) -- adult, September - October 2011, November 2013, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) adult GK5T September 06 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
9149.jpg (76564 bytes)Great Black-backed Gull (Larus marinus) adult: September 23 2011, Scheveningen, the Netherlands.
9149.jpg (76564 bytes)Great Black-backed Gull (Larus marinus) adult: September 23 2011, Scheveningen, the Netherlands.

6200.jpg (74250 bytes)Great Black-backed Gull (Larus marinus) adult: September 17 2001, Bergen op Zoom, the Netherlands.
Primary P5 is fully grown while P8-P10 still have to be shed.

9094gbbg.jpg (65515 bytes)Great Black-backed Gull (Larus marinus) adult: September 19 2003, IJmuiden, the Netherlands.

4913.jpg (56940 bytes)Great Black-backed Gull (Larus marinus) adult: September 22 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Primary P5 is fully grown.

5013.jpg (63424 bytes)Great Black-backed Gull (Larus marinus) adult: September 22 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Primary P6 is fully grown.

5116gbbg.jpg (50480 bytes)Great Black-backed Gull (Larus marinus) adult: September 24 2002, IJmuiden, the Netherlands.
Primary P6 levels with P5 and P10 is still present.

6429.jpg (71014 bytes)Great Black-backed Gull (Larus marinus) adult: September 30 2001, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Primary P5 still isn't fully grown.

6448.jpg (59535 bytes)Great Black-backed Gull (Larus marinus) adult: September 30 2001, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Primary P5 is fully grown. Outer primaries P9-P10 still have to be shed.

6450.jpg (71109 bytes)Great Black-backed Gull (Larus marinus) adult: September 30 2001, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Primary P6 is almost fully grown.

6461.jpg (76161 bytes)Great Black-backed Gull (Larus marinus) adult: September 30 2001, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
Group of Great Black-backed Gulls and Herring Gulls (L. argentatus) at Le Portel.