Lesser Black-backed Gull (graellsii & intermedius)
(last update:
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
adult: March
Colony at "quai de la loire" at Calais, NW France. This is a mixed colony of Lesser Black-backed Gulls and Herring Gulls, with Lesser Black-backeds dominating. Theer are now about 200 pairs breeding. Picture from April 14 2014 (Jean-Michel Sauvage).
LBBG graellsii in spring: open wings.
Pictures of several birds March 17-24 2015 at leiden, the Netherlands. These will probably breed in this area, sometimes called "Dutch intergrades" or "continental graellsii", and birds are a shade arker grey on upperparts than British graellsii, matching many intermedius from Denmark or S Norway.
 |
 |
| Lesser Black-backed Gull EV adult, March 24 2015, Leiden, the Netherlands. | Lesser Black-backed Gull N03J adult, March 24 2015, Leiden, the Netherlands. |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
LBBG returning to the colonies in the Netherlands
End of
March; many adult LBBG of the Maasvlakte (see
map) already return
to the breeding grounds and try to find nesting locations in the colonies.
Successful adults are very faithful to nesting locations and partners and
can be found breeding on exactly the same spot (inch-perfect!) year after
year. Adult males, returning early in the colony normally wait for the
same partner, establishing dominance over a last-year's successful
territory. If the female arrives later in the season, other female try to
mate with such dominant males, but once his partner arrives, the bond will
soon be established and those (often young) females are kicked out the
territory.
By the end of March, 1.000s of LBBG (probably mostly originating from intermedius populations in Scandinavia) migrate east-northeast along the coast-line
of the Netherlands and make short stop-overs at the beach. Well over 90% of the birds
are adults and trains of birds glide motionless over the beaches of the
Wadden Isles into the Danish Wadden Sea.
 LBBG, April 16 2001, Nachtegalenkeet Maasvlakte, the Netherlands. An image showing the difference in grey tones between two
adult LBBG, breeding in the Netherlands. |
At the Maasvlakte, most major position are taken again in the colony by another
type of LBBG: Dutch intergrades. The are slightly darker than typical graellsii from Britain, but not as dark as the average intermedius from
Scandinavia. They carry the genetic heritage of both taxa. The exchange of
gene pools hasn't stopped yet. Still, in the colonies at Maasvlakte we see
foreign ringed birds, breeding together with local Dutch birds. Not
surprising, these foreign birds often seem to be females.
In the mean time birds born in colonies at Maasvlakte spread to other
colonies abroad as well. The very prosperous colony at the Belgium port of
Zeebrugge was initiated by both British and Dutch LBBG, as several colour-ringed
birds proved.
Primary Moult Scores in adult LBBG:
Year 2003 we did some preliminary research on primary moult scores in adult LBBG. In total, we scored about 1400 birds from early April to mid October. This research will be used to do some more fundamental research in tear 2003-2004. First results for April are quite simple: we scored 49 birds on April 05 and we scored 45 birds on April 19. All these birds had P1 still present, hence PMS = 0. Nevertheless we did see several adult LBBG in the colony, which had P1 shed by April 19. Some notes: the scorse on April 05 2003 were done at Naaktstrand, on preening, bathing and arriving birds, through 20x-60x telescopes. Active moult would be noticed, but to detect arrested moult in such circumstances is pretty difficult. Next year, we try to start our surveys with catching birds and examine the exact primary stage in the inner primaries by taking photographs.
Tables & Graph
Table below: data for the Netherlands (2000-2010), results for April (aggregated week): number of remaining old primaries in adults.
REM10 = 10 primaries still old (hence, complete moult not started yet). First signs of complete moult commencement in WEEK 18 (starting 30 April).
| starting date:
|
|
|
16 Apr | 23 Apr | 30 Apr |
|
| week no:
|
9
|
14
|
16
|
17
|
18
|
19
|
| REM 0
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 1
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 2
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 3
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 4
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 5
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 6
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 7
|
0
|
0
|
0
|
0
|
0
|
0
|
| REM 8
|
0
|
0
|
0
|
0
|
15
|
11
|
| REM 9
|
0
|
0
|
0
|
0
|
40
|
34
|
| REM 10
|
2
|
49
|
45
|
1
|
466
|
216
|
|
|
|
|
|
|
|
|
| n =
|
2
|
49
|
45
|
1
|
521
|
261
|
| average P =
|
10.0
|
10.0
|
10.0
|
10.0
|
9.9
|
9.8
|
| 95% CID =
|
0.00
|
0.00
|
0.00
|
- | 0.04
|
0.06
|
| inverse =
|
12.71
|
2.01
|
2.02
|
- | 1.96
|
1.97
|
| Variantie (s2) =
|
0.00
|
0.00
|
0.00
|
- | 0.17
|
0.25
|
| SD (s) =
|
0.00
|
0.00
|
0.00
|
- | 0.42
|
0.50
|
| SE (sx) =
|
0.00
|
0.00
|
0.00
|
- | 0.02
|
0.03
|
|
|
|
|
|
|
|
|
| % class:
|
|
|
|
|
|
|
| 0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 1
|
0
|
0
|
0
|
0
|
0
|
0
|
| 2
|
0
|
0
|
0
|
0
|
0
|
0
|
| 3
|
0
|
0
|
0
|
0
|
0
|
0
|
| 4
|
0
|
0
|
0
|
0
|
0
|
0
|
| 5
|
0
|
0
|
0
|
0
|
0
|
0
|
| 6
|
0
|
0
|
0
|
0
|
0
|
0
|
| 7
|
0
|
0
|
0
|
0
|
0
|
0
|
| 8
|
0
|
0
|
0
|
0
|
3
|
4
|
| 9
|
0
|
0
|
0
|
0
|
8
|
13
|
| 10
|
100
|
100
|
100
|
100
|
89
|
83
|
|
|
|
|
|
|
|
|
|
|
100
|
100
|
100
|
100
|
100
|
100
|
.
Above: Scatter Plot for PMS in adult Lesser Black-backed Gulls. Number of remaining old primaries throughout the year (arrested moult excluded). Sample size is 6.171 birds.
Above: Scatter Plot for PMS in adult Lesser Black-backed Gulls. Number of remaining old primaries for April (arrested moult excluded). Sample size for this graph is 879 ringed birds.
starting date:
|
30 Apr
|
07 May
|
week no:
|
18
|
19
|
NEW 0
|
457
|
205
|
NEW P1
|
10
|
3
|
NEW P2
|
3
|
1
|
NEW P3
|
0
|
0
|
NEW P4
|
0
|
0
|
NEW P5
|
0
|
0
|
NEW P6
|
0
|
0
|
NEW P7
|
0
|
0
|
NEW P8
|
|
0
|
NEW P9
|
|
|
NEW P10
|
|
|
|
|
|
n =
|
470
|
209
|
average NEW P =
|
0.0
|
0.0
|
95% CID =
|
0.02
|
0.02
|
inverse =
|
1.97
|
1.97
|
Variantie (s2) =
|
0.05
|
0.03
|
SD (s) =
|
0.21
|
0.18
|
SE (sx) =
|
0.01
|
0.01
|
|
|
|
% class
|
|
|
0
|
97
|
98
|
1
|
2
|
1
|
2
|
1
|
0
|
3
|
0
|
0
|
4
|
0
|
0
|
5
|
0
|
0
|
6
|
0
|
0
|
7
|
0
|
0
|
8
|
0
|
0
|
9
|
0
|
0
|
10
|
0
|
0
|
|
|
|
% control:
|
100
|
100
|
Table above, data for the Netherlands (2000-2010), results for April (aggregated week): number of new, fully grown primaries in adults.
NEW0 = no new primaries visible (arrested moult excluded in this analysis). So either P1 still old, or P1 dropped, but the very tip still not visible.
NEW1 = P1 longest new primary. Range between "at least the tip of P1 is visible" until "tip of P2 still shorter than P1".
NEW2 = P2 longest new primary. NEW3 = etc.
Above: Scatter Plot for PMS in adult Lesser Black-backed Gulls. Longest new primary is classified "fully grown". Sample size is 2.969 birds. Birds scored on NEW primaries (arrested moult excluded).
The last scoring days were in November, with a larger sample (133 adults) on 04 November 2010. From that date we have the last birds with retaining old primaries (13 birds with 1, 2 or even 3 old primaries; 120 birds with no old primaries left). From other days in November, only 10 birds were scored (all ringed adults). They all had no old primaries left.
The first tine a new primary (P1) was visible, was on 08 May 2006. Prior to this date, birds were scored missing inner primaries, but the very tip was still not visible (and therefore not scored). As soon as the tip of P1 was visible, this was automatically scored "fully grown" For the other primaries to be scored fully grown, they had to exceed the previous primary in length (so P2 fully grown, only from when it is longer than P1).
|
Netherlands
|
|
||||
|
PMS range
|
N:
|
Average PMS
|
PMS range
|
N:
|
Average PMS
|
1-15 apr
|
10
|
49
|
10
|
8-10
|
216
|
9,9
|
16-30 apr
|
10
|
47
|
10
|
10
|
197
|
10,0
|
1-15 may
|
8-10
|
849
|
9,8
|
8-10
|
167
|
9,9
|
16-31 may
|
7-10
|
380
|
9,7
|
7-10
|
76
|
9,5
|
1-15 jun
|
8-10
|
104
|
9,6
|
7-10
|
33
|
8,6
|
16-30 jun
|
7-10
|
253
|
9,7
|
6-10
|
65
|
8,2
|
1-15 jul
|
6-10
|
605
|
9,2
|
5-10
|
176
|
7,4
|
LINEAR REGRESSION
Onset of primary moult can best be illustrated by a sinusoid for the first few weeks and last weeks, but there appears to be linear dependency over much of the central moult period.
The earliest date for birds with missing primaries is 30 April 2006, which is not the earliest day in our complete sample. We scored 98 Lesser Black-backed Gulls prior to that date, some already in February. As can be expected, none of these was in primary moult, and this group was excluded in our further analysis as it will only result in a misfit for the onset of moult, using linear regression statistics.
LINEAR REGRESSION FOR OLD REMAINING PRIMARIES
Complete sample: Linear regression (n = 6171, R2= 0.820, sign: P<0,000)
PMS = -0,381* WEEK + 17,967
Ringed adults: Linear regression (n = 2069, R2= 0.800, sign: P<0,000)
PMS = -0,325* WEEK + 16,270
Unringed adult: Linear regression (n = 4102, R2= 0.779, sign: P<0,000)
PMS = -0,513* WEEK + 23,031
LINEAR REGRESSION FOR NEW FULLY GROWN PRIMARIES
Complete sample: Linear regression (n = 2969, R2= 0.930, sign: P<0,000)
PMS = 0,302* WEEK - 5,933
Ringed adults: Linear regression (n = 1209, R2= 0.888, sign: P<0,000)
PMS = 0,252* WEEK - 4,747
Unringed adult: Linear regression (n = 1760, R2= 0.833, sign: P<0,000)
PMS = 0,442* WEEK - 11,906
Adult intermedius from Norway
.
Lesser Black-backed Gull intermedius JK3S 6CY, March 14 2010, Madrid, Spain. Photo by Delfín González.
Lesser Black-backed Gull intermedius JLK7 10CY, March 10 2017, Matosinhos, Portugal. Picture: José Marques.Adult intermedius from Denmark
.
Lesser Black-backed Gull intermedius V.104 9CY, March & November - December 2016, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull intermedius V.C6K 7CY, March & November - December 2016, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.Adult graellsii from the Germany
.
Lesser Black-backed Gull graellsii H.059 10CY, March 06 2016, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.Adult graellsii from Iceland
.
Lesser Black-backed Gull graellsii YJ56 adult, March 11 2016, Matosinhos Beach, Matosinhos, Portugal. Picture: José Marques. Adult graellsii from the UK
.
Lesser Black-backed Gull graellsii T:87J adult, October 2016 - March 2017, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii 2CK7 5CY, March 12 2016, Aguda beach, V.N.Gaia, Portugal. Picture: José Marques. 
Lesser Black-backed Gull graellsii 4AX5 adult, March, October - December 2015, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii 5FA2 4CY-5CY, October 2016 - March 2017, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii 6AN1 5CY, March & September - October 2016, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii 7AK6 7CY-8CY, March 2016 & February 2017, Aguda beach, V.N.Gaia, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii FLV 15CY-18CY, March 25 2012 & April 07 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve & Maarten van Kleinwee.
Lesser Black-backed Gull graellsii 6SF 5CY & 7CY, March & October 2015, February 2017, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii M+N 5CY & 7CY, March 2015 - February 2017, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii JS adult, November 2016 & March 2017, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii BTO GG49760 19cy & 21cy, 2012 & 2014, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii BTO GH-... adult, Dintelhaven, Maasvlakte, the Netherlands (51.59N,04.02E), March 30 2002. Now breeding in Holland.Adult graellsii from Spain
.
Lesser Black-backed Gull graellsii ZMAC 13CY-14CY, March 2015 & October 2016, Matosinhos, Portugal. Picture: José Marques.Ringed as pullus!
Adult graellsii from France
.
Lesser Black-backed Gull graellsii 001N 5CY-8CY, 2009, 2010 & 2012, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 359N 6CY-9CY, April 2011-2014, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 600N 4CY-6CY, 2010-2012, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 870N 4CY-5CY, 2012-2013, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 918N 5CY-6CY, March - May 2013 & April 2014, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 989N 5CY & 8CY, 2010 & 2013, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii FRP EA676435 adult, March 23 2014, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.Adult graellsii "Dutch intergrade" from Belgium
.
Lesser Black-backed Gull graellsii HKAB 5CY-6CY, 2012 & 2013, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii KJAM 7CY-8CY, April 23 2014, Calais, NW France. Picture: Jean-Michel Sauvage. Also in 2013.
Lesser Black-backed Gull graellsii NHAH 4CY-6CY, July 2013, April 2014, March-May 2015, Calais, NW France & Portugal. Picture: Jean-Michel Sauvage & José Marques.
Lesser Black-backed Gull graellsii BLB L906179 6CY-9CY, 2010-2013, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii BLB L906873 8CY, March 29 2013, Outreau, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii BLB L910624 6CY, March 27 2014, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.Adult graellsii "Dutch intergrade" from the Netherlands
.
Lesser Black-backed Gull graellsii 5.L 6CY, March 09 2017, Matosinhos, Portugal. Picture: José Marques.
LesserBlack-backed Gull graellsii DV adult, March 31 2018, Utrecht, the Netherlands.
Lesser Black-backed Gull graellsii Y.6 6CY, March 09 2017, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii B3 adult, March 26 & April 20 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii BF adult, March 30 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii BW adult, March 26 & June 08 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii BZ adult, March 30 & May 21 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii CN adult, March 30 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii B5 March 22 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii HE adult, March 24 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii VP adult, April 2006 & March 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii TT adult, March 02 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii 12 adult, March 01 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii BH adult, March 22 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii C4 adult, March 09 2009,Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii JH adult, May 2005 & March 2014, Moerdijk & Sassenplaat, the Netherlands. Picture: Merijn Loeve & Mars Muusse.
Lesser Black-backed Gull graellsii JX adult, March 26 2006, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii K6 adult, May 2005 & May 2014, Moerdijk & Sassenplaat, the Netherlands. Picture: Merijn Loeve & Mars Muusse.
Lesser Black-backed Gull graellsii KS adult, March 01 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii OV 6cy-10cy, 2010-2014, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii 03 6CY, March 08 2013, Dordrecht, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii 7W 7CY-8CY, April 08 2014 & March 23 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii AL adult, March 02 2008, Dordrecht, the Netherlands. 
Lesser Black-backed Gull graellsii BA adult, March 01-02 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii G4 adult, March 02 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii J5 adult, March 02 2008, Dordrecht, the Netherlands.
Lesser Black-backed Gull graellsii RF adult, March & September 2016, Matosinhos beach, Matosinhos, Portugal. Picture: José Marques.
Lesser Black-backed Gull graellsii AA adult, March 21 2015, Dordrecht, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii GS 9CY, March 23 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii NL (was EAU7) 10CY & 18CY, May 2006 & March 2014, Moerdijk, the Netherlands. Picture: Merijn Loeve & Mars Muusse.
Lesser Black-backed Gull graellsii 0= adult, March 31 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii 2= adult, March 23 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii A+ 17CY-20CY, March 2012 & 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve & Maarten van Kleinwee.
Lesser Black-backed Gull graellsii M= adult, March & July 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii R= adult, March & May 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii T= adult, March 31 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii KARC 6CY, February 06 & March 06 2016, Comenar Viejo, Madrid, Spain (40°15'41"N 003°38'00"W). Picture: Delfín Gonzalez.
Lesser Black-backed Gull graellsii KJAZ adult, March 18 2015, Leiden, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii YBHR adult, March 06 2016, Comenar Viejo, Madrid, Spain (40°15'41"N 003°38'00"W). Picture: Delfín Gonzalez.
Lesser Black-backed Gull graellsii E B85 13CY, March 31 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii E A17 14CY, March 30 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii E B 11CY & 14CY, April 01 2012 & March 26 - April 10 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve & Maarten van Kleinwee. , geringd in winter london in 2011 02.jpg)
Lesser Black-backed Gull graellsii PB6T adult, March 28 & May 02 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii WH4T adult, March 28 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii CH9 11cy, March 18 2002, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E). An adult male ringed, left orange CH9, ringed as a pullus in July 1992.
Lesser Black-backed Gull graellsii EM7 10cy, March 18 2002, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E). An adult male ringed, left orange EM7.
Lesser Black-backed Gull graellsii E342 8cy, March 18 2002, Nachtegalenkeet, Maasvlakte, the Netherlands (51.59N,04.02E). An adult male ringed, left orange E342, July 8 1995. 
Lesser Black-backed Gull graellsii E600 8cy, Nachtegalenkeet, Maasvlakte, the Netherlands (51.59N,04.02E), March 30 2002.
Lesser Black-backed Gull graellsii E920 8cy, March 18 2002, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E). 
Lesser Black-backed Gull graellsii EC40 7cy, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E), March 30 2002. An adult bird ringed left orange EC40. This is probably a male, as the dominant expression suggests.
Lesser Black-backed Gull graellsii EE23 15CY & 21CY, March 2010 & April 2016, IJmuiden, the Netherlands. Picture: Mars Muusse & Jan Zorgdrager.
Lesser Black-backed Gull graellsii EM41 19CY-20CY, May 23 2014 & March 30 2015, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii EN84 adult, March 18 2002 & April 05 2003, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E).
Lesser Black-backed Gull graellsii EAY0 15cy, March 18 & April 22 2002, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E). The first of birds An adult ringed, left orange EAY0, originating from Britain, ringed in 1988. 
Lesser Black-backed Gull graellsii ECJ3 20CY, March 23 2015, Maasvlakte - Europoort, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii MU6 adult, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E), March 30 2002. An adult bird ringed left leg orange MU6.
Lesser Black-backed Gull graellsii NT0 6cy, March 18 2002, Missouriweg, Maasvlakte, the Netherlands (51.59N,04.02E). An adult female ringed, left orange NT0 in white letters. 
Lesser Black-backed Gull graellsii LL1 8CY-9CY, 2001 & 2002, ECT centrale Maasvlakte, the Netherlands (51.59N,04.02E). Ringed June 28th 1993. Probably a male.
Lesser Black-backed Gull graellsii NV4 9CY & 11CY, 2002 & 2004, Dintelhaven, Maasvlakte, the Netherlands (51.59N 04.02E). 
Lesser Black-backed Gull graellsii E398 8cy, March 30 2002, Dintelhaven, Maasvlakte, the Netherlands (51.59N,04.02E). This bird was ringed June 28 1995 close to the current breeding spot.
Lesser Black-backed Gull graellsii EV41 6cy Dintelhaven, Maasvlakte, the Netherlands (51.59N,04.02E), March 30 2002.
Lesser Black-backed Gull graellsii SL2 15cy, March 11 2012, Maasvlakte, the Netherlands.
Lesser Black-backed Gull graellsii N06A adult, March 28 2014, Maasvlakte, the Netherlands. Picture: Merijn Loeve.
Lesser Black-backed Gull graellsii =1 15CY, March 19 & 31 2011, IJmuiden, the Netherlands.
Lesser Black-backed Gull graellsii E301 E 14CY, March 30 2013, Voorhout, the Netherlands.
Lesser Black-backed Gull graellsii E734 11+cy, March 24 2010, IJmuiden, the Netherlands.
Lesser Black-backed Gull graellsii B64 5cy, March 05 2006, Madrid, Spain. Picture: Delfín González.
Lesser Black-backed Gull graellsii NLA 5.462.840 9CY, March 31 2018, Utrecht, the Netherlands.
Lesser Black-backed Gull graellsii NLA 5.417.298 adult, May & June 2015 & March 2016, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull graellsii NLA 5.410.0xx 14CY, March 30 2015, Leiden, the Netherlands.UNRINGED FLYING ADULT PLUMAGE
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands.
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands. Primary coverts may indicate younger adult (4CY-6CY).
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands.
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands.
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands. P1 new, contrasting with older P2 and adjacent inner primaries.
Lesser Black-backed Gull adult, March 30 2015, Leiden, the Netherlands.