Lesser Black-backed Gull (graellsii & intermedius)

(last update: 14-11-2017 )

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LBBG rings

lbbg 1cy May
lbbg 1cy June
lbbg 1cy July
lbbg 1cy August
lbbg 1cy September
lbbg 1cy October
lbbg 1cy November
lbbg 1cy December

lbbg 2cy January
lbbg 2cy February
lbbg 2cy March
lbbg 2cy April
lbbg 2cy May
lbbg 2cy June
lbbg 2cy July
lbbg 2cy August
lbbg 2cy September
lbbg 2cy October
lbbg 2cy November
lbbg 2cy December

lbbg 3cy January
lbbg 3cy February
lbbg 3cy March
lbbg 3cy April
lbbg 3cy May
lbbg 3cy June
lbbg 3cy July
lbbg 3cy August
lbbg 3cy September
lbbg 3cy October
lbbg 3cy November
lbbg 3cy December

lbbg sub-ad January
lbbg sub-ad February
lbbg sub-ad March
lbbg sub-ad April
lbbg sub-ad May
lbbg sub-ad June
lbbg sub-ad July
lbbg sub-ad August
lbbg sub-ad Sept
lbbg sub-ad Oct
lbbg sub-ad Nov
lbbg sub-ad 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 November
lbbg adult December

first calendar year: December

By November, many LBBG have left the colonies and surrounding feeding grounds near the Maasvlakte (the Netherlands) and have migrated south towards France, Portugal, Morocco and Senegal. By mid-November, several 100's LBBG may still stay near the Maasvlakte, probably as long as it's not freezing. By December, a couple of hundreds remain on continental NW Europe, as north as southern Netherlands along the coast at Westkapelle, 65 km south of the Maasvlakte (see map). As it seems, every year a larger group of LBBG stay "at the most northern latitude as possible", i.e. migrate south only when winter conditions or food supply force them to. They feed out on the North Sea and follow coasters and fishing trawlers in mixed flocks of mainly Herring Gull (argentatus and argenteus) and (in winter only a few) Yellow-legged (michahellis) and Caspian Gulls (cachinnans). 

Year 2000 had a rather mild winter with temperatures below zero as late as mid-December. At Westkapelle, ringed individuals from Scandinavia, Denmark, the Netherlands, Belgium and Britain were present. When winter really started in December, this group moved south as well, to unknown wintering grounds, probably the Atlantic coast of Western and SW Europe. 

The first weeks of November 2001 proved to be mild again and several 100's of LBBG (many adults) could be found at southern locations in the Netherlands: the Maasvlakte and Westkapelle. As in the previous year, red colour-ringed juveniles from the Maasvlakte (the Netherlands), a green colour-ringed 2cy LBBG from Helgoland (Germany) and blue colour-ringed juveniles from Vest-Agder (southern tip of Norway) were present, together with several metal-ringed juveniles from Belgium, Britain, Norway, Denmark, Sweden and the Netherlands. Westkapelle seems to be one of the best places to watch graellsii and intermedius LBBG  together from a short distance.

Comparison of 1CY November taxa:

fuscus C70F 2CY, January 22 2011, Ashdod, Israel (Amir Ben Dov). New scapulars blackish grey. Late moult, and juvenile feathers still in good condition.	michahellis 1G6 1CY, November 15 2009, Madrid, Spain (Delfín González). Extensive post-juvenile moult in coverts and tertials finished.
marinus 97M 1CY, November 27 2013, Boulogne-sur-Mer, France (Jean-Michel Sauvage). Heavy bill, small eye, short primary projection.	cachinnans PHUK 1CY, November 26 2011, Minden, Germany (Armin Deutsch). White-headed, all scaps replaced and commonly some coverts replaced. Often white underwing.
smithsonianus ALB 1CY, November 09 2013, Ocean City, MD (Clive Harris). Solid brown texture on underparts, heavily barred uppertail and undertail covert, almost all black tail.	heuglini 1CY, November 30 2009, northern Oman (Hans Larsson. Some scaps replaced; juvenile feathers still neat.
argentatus J1490 1CY, November 27 2011, Boulogne-sur-Mer, France (Jean-Michel Sauvage). Bird from northern stock: scapulars still neat and almost all are juvenile.	argenteus A5UW 1CY, November 09 2008, Boulogne-sur-Mer, France (Jean-Michel Sauvage). From the U.K. all scaps replaced, tertials deeply notched.
argentatus RUM C-730184 1CY, December 09 2010, IJmuiden, the Netherlands (Mars Muusse). Lower scaps still juvenile.	argenteus VLC 1CY, December 03 2012, Boulogne-sur-Mer, France (Jean-Michel Sauvage). From the U.K. all scaps replaced.
argentatus KV48 1CY, December 31 2006, Oostende, Belgium (Francois Roland). Lower scaps still juvenile.	argenteus YAMF 1CY, December 09 2010, IJmuiden, the Netherlands (Mars Muusse). Almost all scaps replaced.

1cy Lesser Black-backed Gull: post-juvenile moult

The partial autumn moult (moult into so-called "first winter" plumage) includes the body and head feathers. This moult starts as soon as the nest is abandoned (especially in southern populations of graellsii) and continues until January. Early graellsii juveniles fledge by late-June in France, Belgium and the Netherlands, intermedius and fuscus fledge only by mid-July in northern Norway.

The post-juvenile moult in the first year is extensive in southern Lesser Black-backed Gull populations and the final stage of this moult is more or less reached by mid November. Northern juvenile intermedius and nominate fuscus postponed the post-juvenile moult until they reach the wintering grounds, hence retain a juvenile plumage in their hatch year.

Although graellsii is well ahead of its cousins fuscus and intermedius on January 01, much changes dramatically in the new year. Intermedius start a late post-juvenile moult, replacing feathers in March-April. Not only the scapulars and inner wing-coverts are replaced, many birds start replacing almost all of the visible wing-coverts and also rectrices. Advanced birds even include secondaries in this late post-juvenile moult and return in fresh 2nd gen plumage in N Europe in June (2nd gen, except for the juvenile primaries).

Fuscus too has a late post-juvenile moult, or shifted first complete moult. Here things are more complicated: some birds follow a moult strategy similar to that of the complete moult in taxa like argentatus, michahellis, cachinnans or graellsii do in their summer. Other 2CY fuscus adopt a strategy outlined above for intermedius, and start replacing primaries after they have moulted the wing-coverts and tail.

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.

After the post-juvenile moult, the head turns paler on throat and forehead. The breast turns paler as well, but most is an effect of bleaching and wear. The feathers on belly and vent remain juvenile in most 1cy graellsii by November.

graellsii S.L 1CY, November 04 2014, Utrecht, the Netherlands (Frank van der Meer). Extensive moult: all scaps replaced and several coverts as well. Moult stage matching many michahellis in November.	intermedius JR2Y 1CY, November 24 2012, Anza, Morocco (Christian Pedersen). Northernmost colony in Norway. Bird still in juvenile plumage.
graellsii 330N 2CY, February 16 2007, Anza-Agadir, Morocco (Morten Helberg). Extensive moult: all scaps replaced and several coverts as well.	fuscus SVS 8115661 1CY, October 12 2008, Tampere, Finland (Hannu Koskinen). Only single scapular replaced.
Dutch intergrade H585 2CY, February 23 2008, Ciudad Real, Spain (Gabriel Martín). All scaps replaced, coverts juvenile.	fuscus 2CY, March 12 2011, Ashdod, Israel (Amir Ben Dov). Starting primary moult at the wintering grounds. Moult in wing similar to that of the complete moult of 2cy graellsii / intermedius, as it takes place in the summer months. While P1 is growing, the central median coverts are dropped. However, many fuscus show replaced rectrices in an early stage; unlike graellsii, which start tail-feather moult when P6 is growing.
Dutch intergrade H713 2CY, April 16 2009, Quarteira, Portugal (Michael Davis). Post-juvenile moult as late as April also occurs in western birds, even including tail and sometimes secondaries in advanced birds (especially intermedius). But primary moult in spring never documented for 2CY graellsii - intermedius.	fuscus C53K 2CY, March 02 2012, Ashdod, Israel (Amir Ben Dov). Active moult in tail. Primaries and secondaries juvenile. In fuscus moult does not necessarily follow the sequence of the "summer complete moult" (which starts with P1, and is only then followed by wing-covert moult and rectrices moult).