Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

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

Great Black-backed Gull 2cy April

Moult timing in first winter birds: August-January

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 in September illustrates that 40% (n = 10) do show the first signs of moult, i.e. new upper scapulars. By October, over 90% (n = 13) replace the upper scapulars and 38% has started moult in the lower scapulars as well. By November the category "Total scapulars" did not hold a single ringed bird scoring "0% 2nd gen scaps". In other words, all the 27 ringed birds in November had replaced at least one or more (upper) scapulars for 2nd gen feathers.

By December, again all ringed birds had at least some new upper scapulars, with many birds categorised ">75% of the upper scpaulars replaced". There may be a bias towards southern populations, as all images on this site are from birds ringed in S Norway or colonies further south like Denmark and France. It remains pure speculation, but it would be interesting to know where very fresh juvenile birds in November, like THIS ONE hatched. Birds similar to this one, but still fresh by 2cy March, are represented by THIS POWERFULL bird, which is believed to have travelled from far northern Europe. A far northern hatching colony does not necessarily reflect late moult in scapulars. In February we photographed this Russian bird from Murmansk, yet with obvious avergae moult scores in the scapulars.

Despite its southern hatching location, this 1cy bird black JJ77, showed only very limited scapular moult by December, and from all 8 ringed birds in December, it was obviously most retarded.

Tables:

Moult in 2cy April GBBG - ringed birds.
CODE  
US
LS
TOT SCAPS
3cl blue britain april
5
2
3
jp625 black norway april
5
4
4
jp728 black norway april
5
4
4
ju161 black norway april
5
4
4
ju161 black norway april
5
4
4
ju818 black norway april
5
4
4
jz409 black norway april
5
4
4
jw530 black denmark april
5
5
5
jw999 black denmark april
5
5
5
jyy47 black denmark april
5
5
5
j38x black norway april
5
5
5
ju754 black norway april
5
5
5
jzl3 blue norway april
5
5
5

below: graph corresponding to data from table 1. n=13. Distribution of replaced scapulars in April 2cy 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 have been replaced).

below: Great Black-backed Gull JA804 illustrates differences in colour and pattern between old juvenile 1st generation scapulars and fresh buffish 2nd generation feathers. Bird ringed as pullus on June 12 2012 at Salvøy, Karmøy, Rogaland, Norway (59°17'54"N 005°12'27"E). Picture: Jean-Michel Sauvage, September 28 2012, Boulogne-sur-Mer, NW France.

below: Distribution of replaced scapulars for "Total scapular region" for months August in hatch year until commencement of first complete moult in April. Classification in 6 classes, running from 0% (no 2nd gen scaps) to 100% (all scaps, including long rear scaps, have been replaced). Only ringed birds, n=238.

The group of birds which score 100% 2nd gen scapulars gradually grow; remember however that 1st cycle birds, especially in March-April, grown fresh upper scapulars again, most probably 3rd gen feathers (feather condition was not scored by us). Figures in the graph may be read reverse, the presence of juvenile feathers decrease over time.

Origin of all 191 ringed bird, used in our sample. Several individual birds observed in more than one month.
britain
13
denmark
25
france
19
germany
3
holland
3
norway
115
russia
2
sweden
1
usa
10
gbbgJZL3073.jpg (78856 bytes)Great Black-backed Gull JZL3 (Larus marinus) 2cy: April 19 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
8902j43a.jpg (64885 bytes)Great Black-backed Gull (Larus marinus) 2cy J38X April 22 2008, Boulogne-sur-Mer, France (50.42 N - 01.34 E). Picture: J-M Sauvage.
5825stavangergbbg.jpg (55334 bytes)Great Black-backed Gull (marinus) JP625 1-2cy, November 2012 & April 2013, Boulogne sur Mer, France. Picture Jean-Michel Sauvage.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JP728 2cy: April 27 2013, Harlingen, the Netherlands. Picture: Chris Grobbe.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JU161 1st cycle (1CY-2CY), December 20 2014 & April 05 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JU754 1st cycle (1CY-2CY), December 2014 & April 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JU818 1st cycle (1CY-2CY), October 2014 - April 2015 , IJmuiden, the Netherlands.
8902j43a.jpg (64885 bytes)Great Black-backed Gull (Larus marinus) JW530 2cy: January & April 2012, Scheveningen & IJmuiden, the Netherlands.
gbbg Great Larus marinus) 2cy JW999 April 24 2012, Boulogne/Mer, France (50.42 N - 01.34 E).
Ringed in Norway, also present in August this year.
jz8mjan.jpg (127846 bytes)Great Black-backed Gull (Larus marinus) JZ409 2CY, February - April 2015, Scheveningen, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) JYY47 1CY-2CY, November 2014, February-July 2015, Scheveningen, the Netherlands.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (Larus marinus) 1VV 1CY-2CY, November 2013 - August 2014, Dublin, Ireland. Picture: Graham Prole & Stephen Lawlor.
7095jp36.jpg (66909 bytes)Great Black-backed Gull (Larus marinus) 3CL 2CY, April - May 2014, Howth, Dublin, Ireland. Picture: Graham Prole.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) DKC 3M-3206 2cy, March - May 2015, IJmuiden, the Netherlands.
Complete moult started.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 2CY, April 05 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 2CY, April 05 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 2CY, April 05 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 2CY, April 05 2015, IJmuiden, the Netherlands.
8471j52c.jpg (85052 bytes)Great Black-backed Gull (Larus marinus) 2CY, April 05 2015, IJmuiden, the Netherlands.
gbbg2cy082.jpg (70197 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 19 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
gbbg2cy085.jpg (75298 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 19 2002, Le Porel - Boulogne sur Mer, France (50.42 N - 01.34 E).
A male.
gbbg2cy09726.jpg (82224 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 19 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).Two images.
gbbg2cy09733.jpg (64532 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 19 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
gbbg2cy103.jpg (95877 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 19 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
0333gbbg.jpg (64992 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 25 2003, Scheveningen, the Netherlands.
0346gbbg.jpg (56970 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 25 2003, Scheveningen, the Netherlands.
3914.jpg (61492 bytes)Great Black-backed Gull (Larus marinus) 2cy: April 2001, IJmuiden, the Netherlands (52.27 N, 4.33 E).