Lesser Black-backed Gull (graellsii & intermedius)

(last update: 20-2-2011)


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

second calendar year: July 

The classification between the three types, as set up in the May and June section, is hard to maintain now moult in all feather groups is going on. Extreme differences may occur in all types. In the general section we describe the extremes as seen in July.

Remiges moult:

The average primary moult score for mid-July is about 25. On average, p7-p10 are still juvenile outer primaries, p4 is the latest full-grown second generation primary, while p5 and p6 are growing. The extremes found in year 2001: 

A: Delayed moult with only p1 and p2 shed, no new primaries growing (photo 20). The primary moult score is only 2. 

B: Most advanced moult by mid-July includes only p10 and p9 still juvenile and p7 already longer than p6, which is full-grown (photo 22). Moult score is 36 here. 
Such tremendous extremes in primary moult pace can probably only be found in the LBBG-complex; none of the other large white-headed gulls in Western Europe share this phenomenon. 

Some odd primary moult strategies may appear as well, e.g. growing p4 while p5 is still not shed (image 9 and 10). Normally, when a new growing p4 is over half of its final length, the next primary (p5) has been dropped, and, not uncommon, p6 as well. Actually, p4 at 50% and p5 still present may be an indication for arresting the primary moult, but there seems to be no good reason for such a moult strategy in July.

By the end of July, the first secondaries are shed. In many cases, the outer group of approximately 4 are shed (S1-4), then a small block of secondaries remain (app. S5-S9) and the inner secondaries (S10~S17) are shed as well, although often a few remain in the inner-arm (app. S15-S16). The secondary moult strategy resembles the strategy of 2cy michahellis in this respect, with the bulk of LBBG being later (August) in the moult of secondaries.

Rectrices moult:

As could be seen in the May Section, some 2cy LBBG had replaced the entire tail by May. This, of course is the early extreme, only shown by the vanguard of 2cy LBBG. Normally, July is the month where 2cy LBBG shows an incomplete tail. But still, all rectrices may be juvenile as well (as can be seen in image 14).

Scapulars and Wing-Coverts:

As can be seen in almost all the pictures, moult is in progress in both the scapulars and wing-coverts. Some advanced individuals have replaced the entire greater covert bar (image 6 and 24), but normally the central greater coverts are missing or still growing. The outer greater coverts are replaced inwards, after outwards moult of the inner (3-5) greater coverts and the two meet at greater covert #8 approximately. By July, the complete median covert bar has normally been replaced and the moult of the lesser coverts is taking place more randomly. The under-wing coverts probably follow the same sequence as the upper-wing coverts. The pattern on second generation under-wing coverts is more contrasting black-white than the old juvenile variegated brownish under-wing coverts. See e.g. image 19.

On average, the tertial moult is in progress, with the upper two tertials missing or growing in most 2cy LBBG (see e.g. image 10 for an individual with average moult pattern by early July).

By July, it is very difficult to be certain of the exact age of some scapulars. As could be seen in the September section of 1cy birds, many individuals moult scapulars to second generation feathers by late summer. By May, 2cy LBBG may show fresh scapulars again and it's hard to exclude that some individuals by then already have third generation, adult-like scapulars. And now again, by July, almost all 2cy LBBG show at least several fresh, recently replaced scapulars of which some may be of fourth generation. It's expected that these 4th generation feathers appear very adult-like and indeed some individuals show abraded plain grey-brown scapulars combined with fresh adult-like feathers. It has to be said that ageing such scapulars is very hard and as long as (at least some) juvenile scapulars appear, fresh scapulars may be only second generation feathers (replaced very late).

Intermedius types:

By July, the majority of the local Dutch 2cy can be found in the Netherlands and this seems to be the period that many passage intermedius migrate north. Going through a group of 2cy LBBG in July (see image 1, 2 & 3), some individuals appear long-winged, short-legged and generally are more elongated than the average local Dutch 2cy LBBGs. In the captions these birds are mentioned "probable intermedius" as we presume these to originate from Scandinavian populations. Regarding moult pace and moult sequence, there is much overlap with the local Dutch LBBGs.

2cy LBBG from the UK: graellsii
2cy Dutch LBBG in February. (79773 bytes)2cy LBBG CCV March, April, July 2008, Ciudad Real, Spain. Picture: Gabriel Martín.
2cy LBBG from Belgium: graellsii "Dutch intergrade"
1996lbbg2cy.jpg (58458 bytes)2cy LBBG L-...709 July 11 2002, Etaples, France (50.42N,1.34E).
2cy LBBG from the Netherlands: graellsii "Dutch intergrade"
2cy LBBG KK July 16 2010 Heemskerk, the Netherlands. Picture: Ruud Altenburg.
2cy LBBG, ringed in the Netherlands. 2cy LBBG C95 E July 2004, Amsterdam, the Netherlands.
1859lbbg528.jpg (65645 bytes)2cy LBBG E528 July 10 & 11 2002, Boulogne-sur-Mer, France (50.42N, 1.34E). This bird was also present in June. Note the differences in moult stage.
2cy LBBG, ringed in the Netherlands. (70964 bytes)2cy LBBG NLA 5.412.281 July 05 2005, Amsterdam, the Netherlands. Also as 1cy.
2cy LBBG, ringed in the Netherlands. (70964 bytes)2cy LBBG NLA 5.462.871 July 29 2011, Barneveld, the Netherlands. Picture Maarten van Kleinwee.
2cy LBBG from N Germany: "Dutch intergrade"
juvenile LBBG in October, ringed in Norway. (131273 bytes)2cy LBBG H595 July 11 2008, Westkapelle, the Netherlands. Picture: Ies Meulmeester. Also as 3cy.
2cy LBBG N031118 June-August 2012, Boulogne sur mer, NW France. Picture: Jean-Michel Sauvage.
2cy LBBG from Denmark: intermedius
2cy intermedius in July, ringed in Norway. (114585 bytes)2cy LBBG intermediusV3SJ July 2010, August 2014 & October 2014, Utrecht, the Netherlands.
2cy intermedius in July, ringed in Norway. (114585 bytes)2cy LBBG intermedius V6TE July 16 2012, Utrecht, the Netherlands.
2cy LBBG from Norway: intermedius
2cy LBBG intermedius JH2N July 12 2013, Utrecht, the Netherlands. Picture: Frank van der Meer.
2cy intermedius in July, ringed in Norway. (114585 bytes)2cy LBBG intermedius 4139760 July 2004, Amsterdam, the Netherlands. From Norway.
2cy intermedius in July, ringed in Norway. (98880 bytes)2cy LBBG intermedius 4105943 July 2005, Amsterdam, the Netherlands. From Norway. Pictures Ruud Altenburg.
2cy LBBG July: unringed
Lesser Black-backed Gull 2CY, July 24 2013, Katwijk, the Netherlands.
Lesser Black-backed Gull 2CY, July 24 2013, Katwijk, the Netherlands.
LBBG 2CY, July 18 2013, Katwijk, the Netherlands. P6/P9.
LBBG 2CY, July 18 2013, Katwijk, the Netherlands. P5/P8.
LBBG 2CY, July 18 2013, Katwijk, the Netherlands. P5/P8.
1835lbbg2cy.jpg (62165 bytes)2cy LBBG, July 10 2002, Boulogne-sur-Mer, NW France (50.42N, 1.34E). The same bird was present in June. Note the moult progress in these two months.