Lesser Black-backed Gull (graellsii & intermedius)

(last update: 09-06-2013)

Home

LBBG rings

lbbg 1cy May
lbbg 1cy June
lbbg 1cy July
lbbg 1cy August
lbbg 1cy September
lbbg 1cy October
lbbg 1cy Nov - Dec

lbbg 2cy Jan-Febr
lbbg 2cy Mar-April
lbbg 2cy May
lbbg 2cy June
lbbg 2cy July
lbbg 2cy August
lbbg 2cy September
lbbg 2cy October
lbbg 2cy Nov - Dec

lbbg 3cy Jan-April
lbbg 3cy May
lbbg 3cy June
lbbg 3cy July
lbbg 3cy August
lbbg 3cy September
lbbg 3cy October
lbbg 3cy Nov - Dec

lbbg sub-ad Jan-April
lbbg sub-ad May
lbbg sub-ad June
lbbg sub-ad July
lbbg sub-ad Aug
lbbg sub-ad Sept
lbbg sub-ad Oct
lbbg sub-ad Nov - Dec

lbbg ad January
lbbg adult February
lbbg adult Mar-April
lbbg adult May
lbbg adult June
lbbg adult July
lbbg ad August
lbbg ad September
lbbg ad October
lbbg ad Nov - Dec


third calendar year: August

In 3cy LBBG many wing-coverts and the uinner primaries are replaced now. There is a large difference between the start and the end of August. Plumage changes into fresh adult-like upper-parts and under-parts. Wing coverts and tertials become (at least) third generation and mantle and scapulars become fourth or even fifth generation, after the moult to third winter plumage. From head to toe you can see the following changes.

  • The bill becomes paler. Variation in bill colour is low. Bills with a black base (present in 9%, n= 100) are rare while some advanced birds (17%) show an adult-like bill. On average, birds show an adult bill with a dark smudge on the upper mandible (74%).
  • The iris turns pale yellow, but a white or darker peppered iris occur.
  • The head varies from all-white without any speckling (old, worn, 15%), finely streaked from crown to neck (65%) to new heavily streaked (20%). Birds actively moulting the head-feathers look spiky.
  • The under-parts are actively moulted into white feathers. Nearly 100% of the birds shows all-white under-parts, a few have streaking in the hind-neck.
  • By the end of August, all 3cy LBBGs show adult grey upper-parts.
  • Many to nearly all 3cy LBBGs have finished moult of mantle and scapulars (by September all birds). The upper-parts resemble adults now (being fourth or fifth generation).
  • Tertials on 3cy LBBGs in August can exist of old 2nd generation (at least) feathers or newly moulted 3rd generation feathers. The difference is obvious: the new tertials resemble adults, contrary to the blackish centred old tertials. About 50% of 3cy LBBGs have all tertials new, with new upper tertials and old lower tertials being second best.
  • The wing-coverts are in active moult, so a gap in the covert bars is very common. The moult starts with the medians. When median covert moult is halfway, birds start moulting the greater and lesser coverts as well, normally starting with inner and outer greaters. Last moulted feathers are the outer lessers.
  • Common moult-state in 3cy LBBGs by late August is:
    new inner and central medians (third generation), 4 new inner greaters (third generation), missing the central greaters and growing the outer-half inwards and 50% of the lessers old. The third generation coverts normally are adult-grey without barring.
  • Primaries are moulted outwards, the primary-score by the end of August averages 34 (n = 26), all birds showing fully grown p4 at least (see table). Third generation primaries are very adult-like but p10 often shows an obvious smaller mirror. (Later in the year, bleaching gives a browner tinge on the primaries than on adults.)
  • Secondaries are dropped inwards, from the moment p5 or p6 is halfway grown, creating a gap from p1 inwards. Only a very few 3cy show secondary-moult in August. No or nearly none 3cy show fully 3rd generation secondaries by the end of August.
  • The under-wing becomes paler, under-wing coverts are replaced by adult-like feathers. The under-wing coverts are probably moulted in the same sequence as the upper-wing coverts.
  • The tail is old, second generation on many birds (60%), in active moult (20%) and fully grown third generation, white or with very restricted black markings (20%). Old worn tail-feathers occur as some 3cy and 4cy LBBGs may moult the tail on the wintering grounds, subsequently returning with a new tail in spring.
  • Leg colour varies from pink to (pale) yellow.
  • Birds with advanced mantle and scapulars already look exactly like 4cy birds as they return by May in the Netherlands.

Tables

  remaining old primaries full-grown new primaries   # of new tertials
  0 1 2 3 4 5 6 p2 p3 p4 p5 p6 p7   0 1 2 3 4 5 6
15/8     2 10 10 3 2 2 4 9 10 3                 1
21/8     2 7 6 3     4 6 6 2     1   2 5 1 2 4
23/8 1 2 12 8 5       1 4 13 9 1       3 5 5 3 12
28/8 2 4 11 6 3         5 7 8 6     1 1 3 10   11
31/8 2 7 14 9 4         6 14 11 5       3 5 12 5 11
  0: no old primaries left, 
1:
only p10 is still old,
6:
p5 still 2nd generation.
p2: only p1-p2 new, others missing or old,
p7: p1-p7 replaced 3rd generation.
 
  lesser coverts   median coverts   greater coverts  
0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5
15/8 1                     1   1        
21/8 4 3 4 4 1 2       2 1 15 1 4 9 1 1 2
23/8 7 4 3 4 4 6         4 24   7 6 2 8 5
28/8 2 1 2 5 9 7         4 22   4 3 2 9 8
31/8   4 10 5 8 9         5 31   5 5 4 9 13
Coverts score with 0 = all old, 1 = 25% new, 2 = 50% new, 3 = 75% new, 4 = 99% new, 5 = 100% new.

 

Primary moult score of 3cy LBBG, at Naaktstrand, Maasvlakte, the Netherlands (51.59N, 04.02E) on August 14 2003.
. P3 fg P4 fg P5 fg P6 fg P8 fg n:
P6-P10 2 - - - - 2
P7-P10 - 7 - - - 7
P8-P10 - 1 10 1 - 12
P9-P10 - - - 14 1* 15
n: 1 8 10 15 1 36
* arrested moult at P8. P1 fg 4th gen, P2 growing, P3 missing, P4-P8 3rd gen, P9-P10 2nd gen.
n = 35; m old P = 1.7; SD old P = 0.95.
P8-P10 = P8-P10 are still old and present.
Further notes: see previous table.

 

Primary moult score in 3cy LBBG, at Westkapelle, the Netherlands (51.33N, 03.25E) on August 15 2003.
. P3 fg P4 fg P5 fg P6 fg P7 fg n:
P6-P10 1 - - - - 1
P7-P10 - 1 1 1 - 3
P8-P10 - - 5 - - 5
P9-P10 - - - 5 - 5
P10 old - - - - 1 1
n: 1 1 6 6 1 15
For notes: see previous table.
Survey group of 82 LBBG, including 15 3cy.

primary moult score in 3cy LBBG, at Maasvlakte, the Netherlands, (51.59N, 04.02E), August 22 2002.

. P6-P10 P7-P10 P8-P10 P9-P10 P10 old  no old P n:
p7 fg - - - 1 3 3 7
p6 fg - - 5 7 - - 12
p5 fg - 3 12 - - - 15
p4 fg 2 1 - - - - 3
? fg - 2 1 - - - 3
n: 2 6 18 8 3 3 40

n = 40; m old P = 2.7; SD old P = 1.21.
P6-P10 = P6-P10 are still old and present.
? fg = fully grown not known. Fully grown primary score most probably P6 or less.
fg = fully grown. In our field surveys, a primary is 'fully grown' when it exceeds the previous feather in the folded wing. Actually,  such 'fully grown' feathers may have to grow a little, but under field circumstances, it's very difficult to find out if the waxy sheath, which is the standard measurement for fully grown primaries, is still present. 

 

primary moult score in 3cy LBBG, IJmuiden, the Netherlands (52.27N, 04.33E), August 30 2002.

. P7-P10 P8-P10 P9-P10 P10 old  no old P n:
p8 fg - - 1* - - 1
p7 fg - - 2 6 6 14
p6 fg - 4 9 - - 13
p5 fg - 4 - - - 4
p4 fg 1 - - - - 1
n: 1 8 12 6 6 33

n = 33; m old P = 1.8; SD old P = 1.12; m new P = 6.3; SD new P = 0.85.
* = arrested moult, P1-P8 moulted earlier on the wintering grounds.
Further notes: see previous table.

 


LBBG 3cy U.K.: graellsii
 

LBBG 3cy France: graellsii
Lesser Black-backed Gull 3cy 328K August 12 2010, Boulogne sur mer, NW France. Picture: Jean-Michel Sauvage.


LBBG 3cy Belgium: graellsii / Dutch intergrade

Lesser Black-backed Gull 3CY U.FAA August 15 2014, Boulogne sur mer, NW France. Picture: Jean-Michel Sauvage.
7163l9833x.jpg (91538 bytes)Lesser Black-backed Gull 3cy L-9833x August 01 2003, Zeebrugge, Belgium.


LBBG 3cy the Netherlands: graellsii / Dutch intergrade

 

3cy LBBG intermedius in July & August, ringed in Norway. (73514 bytes)Lesser Black-backed Gull 3cy 4.H July & August 2013, Utrecht, the Netherlands. Picture: Herman Bouman.
8242.jpg (73514 bytes)Lesser Black-backed Gull 3cy 01 August 02 2012, , Tilburg, the Netherlands.
8242.jpg (73514 bytes)Lesser Black-backed Gull 3cy YR August 02 2012, , Tilburg, the Netherlands.
 

LBBG 3cy Germany: graellsii-intermedius
Lesser Black-backed Gull 3cy H.319 August 13 2010, IJmuiden, the Netherlands.
Lesser Black-backed Gull 3cy HC59 August 02 2012, Tilburg, the Netherlands.

LBBG 3cy Denmark: intermedius
 

LBBG 3cy Norway: intermedius
Lesser Black-backed Gull 3cy J72P August 08 2009, Calais, NW France. Picture: Jean-Michel Sauvage.
8242.jpg (73514 bytes)Lesser Black-backed Gull 3cy J7T3 August 14 2010, Heemskerk, the Netherlands.
3cy LBBG intermedius in July & August, ringed in Norway. (73514 bytes)Lesser Black-backed Gull 3cy JJ6L July & August 2013, Utrecht, the Netherlands. Picture: Herman Bouman.
8242.jpg (73514 bytes)Lesser Black-backed Gull 3cy JYV1 August & September 2011, Utrecht, the Netherlands. Picture: Herman Bouman & Frank van der Meer.
juvenile LBBG in September, ringed in Norway. (73485 bytes)Lesser Black-backed Gull 2cy-3cy-4cy JZZ7 2010-2012. Pictures Christian Pedersen, Maarten van Kleinwee & Theo Muusse.
8242.jpg (73514 bytes)Lesser Black-backed Gull 3cy J4A3 July 25 & August 21 2003, IJmuiden, the Netherlands.

Sweden: LBBG 3cy: intermedius
 
LBBG 3cy unringed
5896.jpg (98154 bytes)LBBG 3cy August 20 & 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 3cy August 18 2001, Missouriweg Maasvlakte, the Netherlands.
4304cy3.jpg (61325 bytes)LBBG 3cy August 22 2002, Papegaaienbek, Maasvlakte, the Netherlands.
LBBG 3cy August 27 2006, IJmuiden, the Netherlands.
 

LBBG 3cy with arrested moult
8472cy3.jpg (78485 bytes) LBBG 3cy August 29 2003, IJmuiden, the Netherlands. Probably intermedius, arrested moult at P8.