Lesser Black-backed Gull- Kleine Mantelmeeuw (graellsii & intermedius)

(last update: 28-2-2011)

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lbbg ad Nov - Dec

second calendar year: August

In Lesser Black-backed Gulls, nearly all feathers are being replaced by August. There may be great differences, both between individual and in time: between the beginning and the end of the month. Many birds change from a grabby immature into a fresh bird with adult-like upper-parts and under-parts. From head to toe you can see the following changes.

  • The bill becomes paler. Variation in bill colour is very obvious now. All-black bills (still present in 20%) show pink bases while some birds (advanced) may show a pink-yellow bill with only a small sub-terminal band. The average birds show a pink bill with a dark distal half.
  • The iris turns paler brown or whitish, the advanced birds already show a yellowish white iris.
  • The head varies from all-white without any speckling or streaking to 'dirty' and heavily streaked on a grey background.
  • The under-parts moult into white feathers, with dark streaks on the flank and at the sides of the breast. Quite some birds show all-white worn under-parts by late August, with only some streaking on the flanks.
  • The mantle and scapulars consist of old worn second or third generation feathers, being plain with a darker shaft-streak and sub-terminal band, and fresh third or fourth generation feathers, being adult-like (though slightly paler than pure adult-grey) and often with a darker shaft-streak or central wedge.
  • At the end of August, the majority of 2cy LBBG shows many third generation mantle-feathers, creating a grey triangle on the back. 
  • The differences in the amount of adult-grey feathers on mantle/scapulars are obvious: some 2cy just have a few grey feathers on the mantle while others have moulted all mantle and scapulars into adult-like third or fourth generation feathers.
  • Most 2cy LBBGs still moult their mantle and scapulars at the end of August (well into September), so the area of grey on the upper-parts may still grow creating the grey saddle, as often seen in 3cy birds returning in spring.
  • Tertials on a 2cy  LBBG in August can exist of old juvenile as well as fresher second generation feathers or (for advanced birds) newly moulted third generation feathers. The juvenile tertials are very worn pale brown, while second generation feathers are all black with a broad white tip (normally with a thumb-print pattern or vermiculation at the sides). New third generation tertials are adult-like grey but may lack the obvious white tip. By August, many birds miss at least some tertials, often the upper tertials. When present, the upper tertials are normally the most recently moulted ones.
  • The wing-coverts are in active moult, so gaps in the covert bars are very common. Normally, moult starts with the median coverts. While moulting these medians, birds start to shed the greaters (and may shed the lessers as well). The inner median coverts are normally moulted from the body to the outer-wing (up to #5 app.), while the outer medians grow towards the body. Normally the meet at the 7th or 8th median covert, counted from the body. The same applies to the greater coverts, where moult normally starts with the inner coverts. Wing covert moult ends with the outer lesser coverts. Often, these feathers may be a clue for the age of a bird.
  • A common state of moult on a 2cy LBBG by mid-August is:
    new inner medians (second generation), a few new inner greaters (second generation), missing outer and central greaters, missing at least the inner half of the lessers and retained outer lessers. The second generation greater coverts are normally blackish with no or faint barring. Second generation medians and lessers contrast with first (juvenile) generation feathers; they are black centred with a whitish fringe or show barring or anchor patterns.
  • The primaries are moulted outwards and at the end of August all present birds (n = 130) showed at least a fully grown p6. The average moult score by the end of the month is 40, with p7 fully grown, p8 half-way and p9 just visible. But some birds scored 35, while some advanced individuals showed scores of 50. Compared to the old juvenile primaries, new primaries are darker (jet black) and have a rounded top. The inner primaries are paler than the outers, often p1 and p2 with a darker shaft on a brownish background.
  • The secondaries are shed inwards, from the moment p5 is half way to fully grown, often creating large gaps from p1 inwards. They are shed simultaneously (a few, about 5, remain juvenile, and are visible as a block at approximately S5-10 and S16-17). Secondaries grow fast; birds with primary moult score 40 already have at least 5 new secondaries, which are black centred.
  • The under-wing becomes paler, as juvenile under-wing coverts are replaced by white or black-and-white (contrasting) 2nd generation feathers.
  • The tail is second generation in many birds, still in active moult on some, but fully grown in many. The new feathers are all-black or white with a broad irregular black band. In many birds the second generation tail shows more black than on the juvenile. By November, some 2cy LBBGs show predominantly white tail-feathers and probably some 2cy moulting the tail-feathers in July are replacing second generation feathers for third generation rectrices.
  • Structurally, LBBG show much individual variation. One bird can easily be as large and robust as a Greater Black-backed gull, while another (like female intermedius) is only slightly larger than Common Gull (L.canus), gently built with an attenuated rear.
  • The more constant colour of the legs is flesh-coloured to pink; only a very few have a hint of yellow.
  • Those birds with advanced mantle and scapulars may look like 3cy birds as they return in the Netherlands by May next year.

Tables:


The tables below show primary scores of 2cy LBBG in August. In the Netherlands, we have seen colour-ringed and metal-ringed birds from British, Belgian, Dutch, German and Scandinavian projects, thus from graellsii, intermedius and Dutch intergrade populations. We therefore do not specify data to taxa level. 
2cy LBBG were identified on primary pattern and upper-part coloration. Primaries are scored fully-grown when a primary exceeds the previous feather in the folded wing. Note that this also includes feathers which would be scored 'just not fully grown' (score 4) in other researches. We choose this score since it proved to be very difficult to establish the presence of waxy sheath on the feather-base in field surveys.
When judging the old primaries, be aware of the dark print on outer primaries, created by the shed, previous feather. Such prints may contrast strongly with the bleached primary tips.

2cy LBBG Maasvlakte - the Netherlands, Aug 14 2003

new P p5 p6 p7 p8 p9 p10 n:
P8 1 - - - - - 1
P9 1 12 - - - - 13
P10 - - 7 - - - 7
no old P - - 9 2 - - 11
n: 2 12 16 2 - - 32

notes:
n old primaries: 32
m old primaries: 1,1
SD old primaries: 0,94
95% CID old primaries: 0,34


n new primaries: 32
m new primaries:6,6
SD new primaries: 0,72
95% CID new primaries: 0,26

2cy LBBG Westkapelle,  the Netherlands, Aug 15 2003

new P p5 p6 p7 p8 p9 p10 n:
P8 2 1 - - - - 3
P9 - 12 - - - - 12
P10 - - 22 - - - 22
no old P - - 3 3 - - 6
n: 2 13 25 3 - - 43

notes:
n old primaries: 43
m old primaries: 1,3
SD old primaries: 0,80
95% CID old primaries: 0,25


n new primaries: 43
m new primaries: 6,7
SD new primaries: 0,68
95% CID new primaries: 0,21

2cy LBBG Maasvlakte - the Netherlands, Aug 22 2002

new P P5 P6 P7 P8 P9 P10 n:
P8 old 2 2 - - - - 4
P9 old - 5 1 - - - 6
P10 old - - 25 2 - - 27
no old - - 12 16 1 - 29
n: 2 7 38 18 1 - 66

notes:
n old primaries: 66
m old primaries: 0,8
SD old primaries: 0,86
95% CID old primaries: 0,21


n new primaries: 66
m new primaries: 7,1
SD new primaries: 0,74
95% CID new primaries: 0,18

2cy LBBG Maasvlakte - the Netherlands, Sept 28 2001

new P P5 P6 P7 P8 P9 P10 n:
. - - 9 26 61 9 105

notes:
n new primaries: 105
m new primaries: 8,7
SD new primaries: 0,76
95% CID new primaries: 0,15

 


2cy LBBG: graellsii


juvenile LBBG, ringed in the Netherlands. LBBG 1PF August 10 2006, Madrid, Spain., the Netherlands. Photo by Delfín González. Also seen in November 2005.

2cy LBBG: 'Dutch intergrade'


2cy LBBG in August, ringed in Belgium. (98089 bytes)LBBG 2cy L-x9892 August 15 2003, Westkapelle, the Netherlands.
2cy LBBG in August, ringed in Belgium. (113933 bytes)LBBG 2cy L-901x95 August 29 2005, Westkapelle, the Netherlands.
2cy Dutch LBBG in February. (79773 bytes)LBBG JG April 2008 - March 2009, Madrid, Spain. Picture: González & Martin.
1cy argenteus in August, ringed in Belgium. (90559 bytes)LBBG AW August 14 2009, Westkapelle, the Netherlands.
2cy LBBG in August, ringed in the Netherlands. (52144 bytes)LBBG 2cy A12E August 14 2003, Naaktstrand, Maasvlakte, the Netherlands.
2cy LBBG in August, ringed in the Netherlands. (54795 bytes)LBBG 2cy A82E August 14 2003, Naaktstrand, Maasvlakte, the Netherlands.
juvenile LBBG, ringed in the Netherlands. LBBG 2cy C95E, August 14 2004, Amsterdam, the Netherlands.
2cy LBBG in August, ringed in the Netherlands. (66391 bytes)LBBG 2cy IE August 29 2003, IJmuiden, the Netherlands.
Lesser Black-backed Gull 2cy N031118June-August 2012, Boulogne sur mer, NW France. Picture: Jean-Michel Sauvage.
2cy LBBG in August, ringed in the Netherlands. (54795 bytes)LBBG 2cy H366 August 03 2009, Barneveld, the Netherlands. Picture: Herman Bouman.
2cy LBBG in August, ringed in the Netherlands. (54795 bytes)LBBG 2cy H871 August 11 2010, Barneveld, the Netherlands.

2cy LBBG: intermedius

1cy argenteus in November, ringed in Belgium. (25637 bytes)LBBG V336 August 26 2009, Westkapelle, the Netherlands.
LBBG intermedius in August, ringed in Norway. (71012 bytes)LBBG V652 August 14 2010, Heemskerk, the Netherlands.
LBBG intermedius in August, ringed in Norway. (71012 bytes)LBBG VH6C August 19 2011, Utrecht, the Netherlands. Picture: Herman Bouman.
juvenile LBBG in September, ringed in Norway. (73485 bytes)LBBG intermedius JXR3 August 24 2010, Westkapelle, the Netherlands.
Also seen as 1cy.
juvenile LBBG in September, ringed in Norway. (73485 bytes)LBBG intermedius JZZ7 2cy-3cy-4cy, 2010-2012. Pictures Christian Pedersen, Maarten van Kleinwee & Theo Muusse.
2cy Dutch LBBG in February. (79773 bytes)LBBG J55P August 21 2008, Farsund, Vest-Agder, Norway. Picture: Finn Jørgensen.
LBBG intermedius in August, ringed in Norway. (71012 bytes)LBBG J93T August 21 2003, IJmuiden, the Netherlands.
LBBG intermedius in August, ringed in Norway. (39271 bytes)LBBG JT74 August 21 2002, Cambridge, U.K. (52.14N 00.09E). Ringed in Norway July 03 2001.

unringed birds in NW Europe

7837cy2.jpg (69895 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
5896.jpg (98154 bytes)LBBG 2cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 2cy August 22 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 2cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 2cy August 20 2012, Katwijk, the Netherlands.
5896.jpg (98154 bytes)LBBG 2cy August 20 2012, Katwijk, the Netherlands.
7844cy2.jpg (61568 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7869cy2.jpg (50035 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7874cy2.jpg (64753 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7885cy2.jpg (85762 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7943cy2.jpg (70048 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7969cy2.jpg (92763 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7983cy2.jpg (73402 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.
7994cy2.jpg (84142 bytes)LBBG 2cy August 15 2003, Westkapelle, the Netherlands.