Lesser Black-backed Gull (graellsii & intermedius)

(last update: 21-2-2011)

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second calendar year: June

First summer (2cy) LBBG can be classified in 3 categories. In the 2cy LBBG May section, we give details about this classification, based on research done last years. Of course, the classification for May applies to June as well. In year 2001, we tried to get more information about the extremes of these classes, especially regarding moult strategy and moult pace.

First type LBBG (local typical 2cy) in June:

The under-parts and head are patterned with bold markings on a dirty base. The partial spring moult involves head and under-parts. By June, birds show neat streaking on head feathers, combined with abraded under-parts (often the vent and flanks).

The scapulars may have been moulted last autumn (as early as September) to anchor patterned second generation feathers. By June, these may be replaced again and the new pattern is largely unpredictable. They may appear adult-like grey or brown-grey, often with a pronounced dark shaft. But the third generation feathers may also show an almost similar pattern as the second generation feathers, again with anchors or barring. 
Some birds may require their first renewed  second generation coverts as late as June. Fresh feathers can be recognized by the white fringe. The juvenile wing-coverts are shed rapidly and new second generation coverts start growing. In some individuals, complete covert-rows have  been shed and the new feathers grow simultaneously. Again, the pattern shows barring or anchors. If the coverts were not moulted on the wintering ground, moult starts with the median covert row, combined by a few inner greater coverts and randomly some lesser coverts (though often in the inner part of the lessers). Normally, this first type LBBG has some remaining juvenile coverts in the carpal edge (outer lesser coverts).

The tail is still largely black-brown and the present rectrices are nearly always juvenile, though central rectrices are shed now.

The bill is mostly blackish with only a slightly paler base. Legs are pink.

All 2cy LBBG show active primary-moult in the inner primaries in the first week of June. On average, towards the end of the month, P4 is growing and P6 is shed.

Above: Classic first type (2CY graellsii type) LBBG, June 24 2013. Head and underparts moulted in spring, now with neat sharply demarcated streaks. No coverts and no tertials replaced on winter grounds, all juvenile prior to northbound migration and now worn. By June, complete moult has started, which is also visible in standing birds: central median coverts are missing, inner median and greater coverts recently replaced again with barred pattern, but note fresh fringes.
Below: First type LBBG, June 24 2013. No coverts and no tertials replaced on winter grounds, all juvenile prior to northbound migration and now worn. By June, complete moult has started, here with P1-P2 new. Simultaneously, outer median coverts are growing (tips just visible), inner median and greater coverts recently replaced again with barred pattern, note cold grey tone, contrasting with bleached pale brown juvenile coverts. Returned from winter grounds with all flight feathers still juvenile and bleached.

Second & third type LBBG in June:

These types show a short neck, small rounded head, fine and short bill, short legs (especially tibia) creating a delicate and compact appearance, in some individuals pronounced by the relatively short primary-projection. Also, plumage and timing of moult in wing-coverts and tail-feathers on average are different from the first type. The first type LBBG start moulting coverts and scapulars at a high pace and especially the primary moult may be more advanced than in the second and third type.

We treat the second and third type together, because in June the differences between these two become less obvious as under-parts become white and the exact pattern of scapulars and coverts is hard to detect on the abraded feathers. As said in the 2cy LBBG May Section, these types already replace scapulars and many wing coverts on the wintering grounds. By June, the pattern gets lost and the fringes get worn. 2cy LBBG belonging to these types start growing third generation coverts now. As mentioned before, third generation coverts may resemble second generation coverts in pattern. Here, in these two types, the third generation coverts are often adult-like plain dark-grey (sometimes with an all-black central wedge), unlike the bared or anchored 2nd generation feathers.

Above: June 24 2013. Second and third type LBBG return from winter grounds with extensive moult in coverts and upper tertials. Here, almost all visible coverts and tertials are 2nd generation. Some coverts show a pronounced dark club-pattern, but in general most coverts are simply patterned: greyish-brown with a darker triangle centre / broad shaft-streak. Note that feathers replaced in winter are worn by June.
Below: Same bird. Outer greater coverts missing, now to be replaced for 2nd generation feathers (arrow B). Central median coverts missing, now to be replaced for 3rd generation coverts (A).

Tail-feather moult

The number of moulted rectrices in the winter-quarters is highly variable and subsequently we find large variation in June. Advanced individuals show a complete second generation tail, while others return in a clearly suspended moult-stage. In the winter-quarters, many individuals do not proceed the moult of the rectrices in a descendant sequence, since migrating birds in spring really show every conceivable moult-stage (e.g. R5-6 second generation, while R1-4 are still juvenile, etc).
Some birds do not show fully-grown rectrices, but it is at least not usual to find a tail in active moult by May and early June. Apart from the obvious fresh white tips, the pattern of the second generation rectrices is mostly juvenile-like, but the darker parts are pure black and the pattern is more vermiculated. However, birds with for example a partially white R2, a nearly complete black R3 and with a R4 showing much white, are common. A small minority shows only very little black on the second generation tail-feathers.
The renewed upper-tail coverts are complete white or with some sparse black barring on a white base.

Above: June 24 2013. Second and third type LBBG may return from winter grounds with replaced rectrices.
Below: June 15 2013 (picture Maarten van Kleinwee). Some intermedius-type birds replace secondaries in winter quarters. Such birds return in spring with fresh-looking coverts, tail and secondaries, but by mid-June, they normally show retarded primary moult (about two weeks later in moult than classic graellsii). Here, PMS is only 11.

Wing-covert moult

The wing-covert moult has mainly been suspended prior to migration, with in most cases a generation contrast between the inner and outer coverts. This especially applies to the greater coverts, which often show a mix of juvenile and 2nd generation coverts, where tertials and median coverts are often already renewed. The moult-stage of lesser coverts is more advanced than the greater coverts, but especially 'upper' lesser coverts are less advanced than the tertials and median coverts. Once returned, many birds start shedding complete covert bars and grow new feathers simultaneously. 

Primary moult

The onset of the primary moult in second and third type 2cy LBBGs in early summer is on average slightly later (1-2 weeks) than in typical first types. Additionally, the individual variation is more pronounced, with e.g. in the third week of June, birds with only P1-2 missing and birds which already shed P7. However, in comparison with the first type, differences in timing of primary moult is usually not significant.

Below: May 15 2010 (picture Amir Ben Dov). If 2CY LBBG arrive in spring with all feather tracts replaced, nominate fuscus is involved.

Tables

 

Primary moult score of 2cy LBBG June 26 2003, at Dannes gravel pit, NW France (50.42N,01.34E).
. no new P1 fg P2 fg P3 fg P4 fg ? fg n:
P3-P10 1 - - - - 1 2
P4-P10 - - - - - 3 3
P5-P10 - - 1 - - 5 6
P6-P10 - - 4 4 - 9 17
P7-P10 - - 1 2 5 4 12
n: 1 - 6 6 5 22 40
n = 40; m old P = 5.2; SD old P = 1.10.
P6-P10 = P6-P10 are still old and present.
? fg = fully grown not known. Often referring to sleeping birds with folded wings, so 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. 

 

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2cy LBBG from the UK: graellsii
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2287fd.jpg (60741 bytes)2cy LBBG FD June 26-28 2003, Boulogne-sur-Mer, France (50.42N,1.34E). Mint-green ring from Britain.
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2cy LBBG from the Netherlands: graellsii "Dutch intergrade"
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1301re528.jpg (84694 bytes)2cy LBBG E528 June 13 & 14 2002, Boulogne-sur-Mer, France (50.42N, 1.34E). P4 is juvenile, P2 is growing. The tail is juvenile.
2cy LBBG, ringed in the Netherlands. 2cy LBBG C95E June 26 2004, Amsterdam, the Netherlands.
2cy LBBG, ringed in the Netherlands. (94332 bytes)2cy LBBG F40E June 30 2005, Amsterdam, the Netherlands.
2cy LBBG, ringed in the Netherlands. (65913 bytes)2cy LBBG 5.179.990 June 12 2005, Amsterdam, the Netherlands. Pullus born near Amsterdam.
2cy LBBG, ringed in the Netherlands. (100770 bytes)2cy LBBG 5.412.311 June 15 2005, Amsterdam, the Netherlands. Pullus born in IJmuiden.
juvenile LBBG in October, ringed in Norway. (131273 bytes)2cy LBBG 5.418.124 June 20 2009, Amsterdam, the Netherlands. Picture: Ruud Altenburg.
juvenile LBBG in October, ringed in Norway. (131273 bytes)2cy LBBG 5.440.093 June 20 2009, Amsterdam, the Netherlands. Picture: Ruud Altenburg.
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2cy LBBG from N Germany: graellsii - intermedius
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1cy argenteus in November, ringed in Belgium. (25637 bytes)LBBG 2cy H460 June 20 2008, Westkapelle, the Netherlands.
Lesser Black-backed Gull 2cy N031118 June-August 2012, Boulogne sur mer, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull 2cy DEH 4279xxx June 24 2013, Noordwijk, the Netherlands.
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2cy LBBG from Denmark: intermedius
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juvenile LBBG in October, ringed in Norway. (131273 bytes)2cy intermedius V247 June 20 2009, Amsterdam, the Netherlands. Picture: Ruud Altenburg.
3cy graellsii LBBG in June, ringed in the Netherlands. (135385 bytes)2cy intermedius VP6K June 16 2013, Noordwijk, the
Netherlands. Picture: Ruud Altenburg.
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2cy LBBG from Norway: intermedius
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3cy graellsii LBBG in June, ringed in the Netherlands. (135385 bytes)2cy intermedius JM4E June 16 2013, Noordwijk, the
Netherlands. Picture: Ruud Altenburg.
2cy LBBG from Norway. (71201 bytes)2cy intermedius J7N5 June 28 2003, Boulogne/Mer, NW France.
1674jxu7.jpg (64892 bytes)2cy intermedius JXU7 June 18 2002, Papegaaienbek - Maasvlakte, the Netherlands.
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2cy LBBG from Sweden: intermedius
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2cy LBBG from Sweden. (92672 bytes)2cy LBBG 8106930 June 12 2005, Amsterdam, the Netherlands. From Sweden.
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2cy LBBG June: ringed in winter
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3cy graellsii LBBG in June, ringed in the Netherlands. (135385 bytes)LBBG N09C 2cy June 16 2013, Noordwijk, the Netherlands. Picture: Frank van der Meer.
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2cy LBBG June: unringed
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2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P1/P3, new tail.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P5, new tail.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P3.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P3.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P3.
2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P1/P3.
2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P1/P4.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P4.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P5, new tail.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P1/P6.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P6, new tail.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P6.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P6.
2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P3/P6.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P3/P6.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P6.
2172.jpg (51826 bytes)LBBG 2cy June 10 2013, Noordwijk, the Netherlands. Complete moult started: P2/P6.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P3/P7.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P3/P7.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P3/P7.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P4/P7.
2172.jpg (51826 bytes)LBBG 2cy June 15 2013, Noordwijk, the Netherlands. Complete moult started: P2/P4. Replaced secondaries in winter. Picture: Maarten van Kleinwee.
2172.jpg (51826 bytes)LBBG 2cy June 07 2013, Noordwijk, the Netherlands. Complete moult started in winter like fuscus, then arrested at P6.
2172.jpg (51826 bytes)LBBG 2cy June 07 2013, Noordwijk, the Netherlands. Complete moult finished in winter like fuscus.
2172.jpg (51826 bytes)Photo 2172: 2cy intermedius, June 26 2003, Boulogne-sur-Mer, France (50.42N, 1.34E). All primaries moulted to 2nd generation, possible fuscus.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
1286.jpg (68670 bytes)Photo 1279: 2cy LBBG, June 14 2002, Boulogne-sur-Mer, France (50.42N,1.34E). P7 is still old. The dark 'shadow-print' of P6 is still visible on P7.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P2/P5.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands. Complete moult started: P7-P10 old juvenile.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.
2172.jpg (51826 bytes)LBBG 2cy June 24 2013, Noordwijk, the Netherlands.