Great Black-backed Gull (Larus marinus)

(last update: October 12, 2011)

Great Black-backed Gull 1cy October

Description of 1st winter plumage

First-winter (Sep-Mar) similar to juvenile, but head and upper breast whiter with narrower dark streaks (especially around eye and on hindneck); forehead normally white. May show dark ear-spot. Mantle and scapulars pale grey to buff with blackish subterminal bars or anchor-shaped spots; often intermixed with juvenile feathers. Bill similar to juvenile, but some develop paler base from early winter. Pale individuals have whitish underparts, narrower dark subterminal marks on upperparts and narrow dark covert-markings. With wear may bleach as described under Herring Gull, but rarely as extreme (an extremely pale spring bird shown by Grant (1989a) could to my eyes be partly leucistic, as the upperparts appear unmarked, which is atypical even in very worn birds). (Malling Olsen, K. & Larsson, H. 2004 Gulls of Europe, Asia and North America. London: Christopher Helm).

Moult into first winter

Juvenile moult to first winter plumage partial Aug-Nov, including mantle, scapulars, and (probably) parts of head and body. Often no sign of moult into Nov/Dec. (Malling Olsen, K. & Larsson, H. 2004 Gulls of Europe, Asia and North America. London: Christopher Helm).

Although Malling Olssen states "often no sign of moult into Nov/Dec", this is not supported by data of ringed birds. The table presented below illustrates that over 90% of the 1cy birds in October (n = 19) do show (at least) the first signs of moult, i.e. new upper scapulars.
By October, over 90% (n = 19) replace the upper scapulars and about 25% has started moult in the lower scapulars as well.

All wing-coverts, tertials and flight feathers still juvenile by October, except for the odd bird in any larger group.

top: marinus 1cy JH837 September 20 2010, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage. All scapulars still juvenile.
Class: US=0%, LS=0%, TOT SCAPS=0% .
below: marinus 1cy JP873 October 23 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage. Five upper scapulars replaced, note the buffish tone in the fresh 2nd gen scapulars.
Class: US=1-25%, LS=0%, TOT SCAPS=1-25%.

Tables:

Moult in 1cy October GBBG - ringed birds.
CODE
US
LS
TOT SCAPS
birds from Norway
blue J5RE
25-50%
25-50%
25-50%
blue J7RH
25-50%
0%
1-25%
blue J9TT
25-50%
0%
1-25%
blue JZ2X
75-99%
50-75%
50-75%
blue JZ4X
75-99%
1-25%
25-50%
blue JAY2
50-75%
0%
1-25%
black JL88
75-99%
25-50%
50-75%
black JM06
1-25%
0%
1-25%
black JA112
1-25%
0%
1-25%
black JE318
0%
0%
0%
black JP784
25-50%
0%
1-25%
black JP873
1-25%
0%
1-25%
black JW353
75-99%
0%
25-50%
black JY283
1-25%
0%
1-25%
birds from France
green M08
25-50%
0%
1-25%
blue 75A
75-99%
25-50%
50-75%
blue 06C
1-25%
0%
1-25%
blue 78C
25-50%
0%
1-25%
blue 78G
1-25%
0%
1-25%

below: graph corresponding to data from table 1. n=19. Distribution of 2nd generation scapulars in October 1cy GBBG, separated into Upper Scapulars, Lower scapulars and for Total scapular region. Classification in 6 classes, running from 0% (no 2nd gen scaps) to 100% (all scaps in a region are 2nd gen).

It is clear from the column "Total scapulars" that less than 10% of the October birds scored "0% 2nd gen scaps", in other words, over 90% of those 19 ringed birds had replaced at least one or more (upper) scapulars for 2nd gen feathers.

Great Black-backed Gull (Larus marinus) 1cy JAY2 October 22 2001, Westkapelle, the Netherlands (51.33 N, 3.25 E).
jz2xwk211004b.jpg (132069 bytes)Great Black-backed Gull (Larus marinus) 1cy JZ2X October 21 2004, Westkapelle, the Netherlands (51.33 N, 3.25 E). Ringed in Norway. Picture Pim Wolf.
jz4xwk211004.jpg (141311 bytes)Great Black-backed Gull (Larus marinus) 1cy JZ4X October 21 2004, Westkapelle, the Netherlands (51.33 N, 3.25 E). Ringed in Norway. Picture Pim Wolf.
gbbgGreat Black-backed Gull (Larus marinus) 1cy J5RE October 19 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
gbbgGreat Black-backed Gull (Larus marinus) 1cy J7RH October 06 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
gbbgGreat Black-backed Gull (Larus marinus) 1cy J9TT October 26 2007, Westkapelle, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 1cy JA112 October 07 2008, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
gbbgGreat Black-backed Gull (Larus marinus) 1cy JE318 October 15 & 19 2009, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) 1cy JP784 October 30 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) 1cy JP873 October 23 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JU402 1CY, October 12 2014, Boulogne sur Mer, France. Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 1cy JW353 October 10 2010, Westkapelle, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) 1cy JY283 October 29 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
gbbgGreat Black-backed Gull (Larus marinus) 1cy JL88 October 21 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
gbbgGreat Black-backed Gull (Larus marinus) 1cy JM06 October 01 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (Larus marinus) 1cy 78G October 07 2010, Boulogne / Mer, France. Picture Jean Michel Sauvage.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (Larus marinus) 1cy 78C October 15 2008, Boulogne / Mer, France. Picture Jean Michel Sauvage.
GBBGGreat Black-backed Gull (Larus marinus) 1cy 06C October 29 2007, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
GBBGGreat Black-backed Gull (Larus marinus) 1cy 57B October 21 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
GBBGGreat Black-backed Gull (Larus marinus) 1cy 75A October 20 2006, Boulogne sur Mer, France (50.44 N - 01.35 E). Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 44S 1CY, October 21 2014, Boulogne sur Mer, France. Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 56P 1CY, October 08 2014, Boulogne sur Mer, France. Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) 1cy M08 October 29 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) M88 1CY, October 10 2014, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (Larus marinus) 3AL 1CY, October - November 2013, Dalkey, Dublin, Ireland. Picture: Stephen Lawlor.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (marinus) 1CY no code October 04 2013, Boulogne sur Mer, France. Picture Jean-Michel Sauvage.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (L. marinus) 1cy, October 11 2011, Scheveningen, the Netherlands.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (L. marinus) 1cy, October 11 2011, Scheveningen, the Netherlands.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (L. marinus) 1cy, October 11 2011, Scheveningen, the Netherlands.
Great Black-backed Gull (Larus marinus) 1cy: October 01 2001, Boulogne sur Mer, France (50.42 N - 01.34 E).
Great Black-backed Gull (Larus marinus) 1cy: October 01 2001, Boulogne sur Mer, France (50.42 N - 01.34 E).
Great Black-backed Gull (Larus marinus) 1cy: October 01 2001, Boulogne sur Mer, France (50.42 N - 01.34 E).
Great Black-backed Gull (Larus marinus) 1cy: October 01 2001, Boulogne sur Mer, France (50.42 N - 01.34 E).
Great Black-backed Gull (Larus marinus) 1cy: October 01 2001, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).