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

(last update: 17-1-2011 )

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lbbg ad Nov - Dec

adult: June

At the Maasvlakte colonies in the Netherlands (see map), eggs are hatched by the first week of June and many nests contain three nestlings (breeding season 2001 and 2002). Pulli can be found everywhere. First data in 2001 estimate the colonies to be expanded by over 20%, now approximately 40,000 nests at the Europoort location alone (greater Rotterdam district). New colonies arise at plots which are still not occupied by industrial companies. 

In this picture you see female E832, ringed at the nest at Maasvlakte July 1995, now in her 6th summer and raising three pulli. Normally the elder adults occupy the sites used last year(s), as these birds know safety, feeding routes and places, etc. New colonies seem to be occupied by younger adults, as some ring-data suggest. Older LBBGs disturbed from 'ancient' colonies seem to move less far from the places they were forced to abandon. It's interesting to find out whether new colonies abroad are started by relatively young adults.

Moult:

Raising pulli is very time consuming and all moult in the wing-coverts is suspended in adults.
In some individuals, head feather moult is started mid-June and only the odd individuals moult coverts at a low pace. 

Counting back from the results of surveys done in August 2001, a small proportion of adult LBBG must have shed inner primaries by June. Last years, we did not collect sufficient material to estimate primary moult scores for this age class in June, so a small survey on 200 adult birds was done. We scored preening and bathing adults from the near colony (several 1.000's breeding pairs). The first estimation was done on arriving birds, checking the age while bathing and check primary moult score again at departure. The table shows the results: 75% of local (!) adult LBBG have still all the primaries old (p1-p10 old) and a small minority of about 20% has started moult with dropping p1.

Tables & Graph

starting date: 28 May 04 Jun 11 Jun 18 Jun 25 Jun 02 Jul
week no: 22 23 24 25 26 27
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 1
REM 7 0 0 0 1 0 14
REM 8 5 3 3 13 0 64
REM 9 12 6 12 45 1 112
REM 10 102 17 28 169 5 127
0 0
n = 119 26 43 228 6 318
average P = 9.8 9.5 9.6 9.7 9.8 9.1
95% CID = 0.09 0.29 0.19 0.08 0.43 0.10
inverse = 1.98 2.06 2.02 1.97 2.57 1.97
Variantie (s2) = 0.24 0.50 0.39 0.36 0.17 0.80
SD (s) = 0.49 0.71 0.63 0.60 0.41 0.89
SE (sx) = 0.04 0.14 0.10 0.04 0.17 0.05
% 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 4
8 4 12 7 6 0 20
9 10 23 28 20 17 35
10 86 65 65 74 83 40
% control: 100 100 100 100 100 100

Table above, data for the Netherlands (2000-2010), results for June (aggregated week): number of remaining old primaries in adults.
REM10 = 10 primaries still old (hence, complete moult not started yet).

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 June (arrested moult excluded). Sample size for this graph is 339 ringed birds + 401 unringed birds.

starting date:

21 May

04 Jun

02 Jul

week no:

21

23

27

NEW 0

92

8

1

NEW P1

4

0

1

NEW P2

0

0

0

NEW P3

0

0

0

NEW P4

0

0

0

NEW P5

0

0

0

NEW P6

0

0

0

NEW P7

0

0

0

NEW P8

0

0

0

NEW P9

0

0

0

NEW P10

0

n =

96

8

2

average NEW P =

0.0

0.0

0.5

95% CID =

0.04

0.00

6.35

inverse =

1.99

2.36

12.71

Variantie (s2) =

0.04

0.00

0.50

SD (s) =

0.20

0.00

0.71

SE (sx) =

0.02

0.00

0.50

% class

0

96

100

50

1

4

0

50

2

0

0

0

3

0

0

0

4

0

0

0

5

0

0

0

6

0

0

0

7

0

0

0

8

0

0

0

9

0

0

0

10

0

0

0

% control:

100

100

100

Table above, data for the Netherlands (2000-2010), results for June (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 throughout the year. Longest new primary is classified "fully grown". Sample size is 2.969 birds. Birds scored on NEW primaries (arrested moult excluded).

Above: Scatter Plot for PMS in adult Lesser Black-backed Gulls. Scoring on longest new primary, which is classified "fully grown" for June (arrested moult excluded). Sample size for this graph is 10 ringed birds.

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.

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).

Peter Stewart presents onset of primary moult by scores for caught adult Lesser Black-backed Gulls in the Severn Estuary, U.K., repeated in the table below. To read his results, see this PDF file.  

Table: the number of old remaining primaries present. Compare PMS of adult graellsii at half monthly intervals. Data from the Severn Estuary Gull Group by Peter Stewart: The primary moult of the Lesser Black-backed Gull (special publication No 1).

 

Netherlands

Severn Estuary U.K.

 

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.

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

Primary moult score of adult LBBG June 18 2002, at Dintelhaven colony, Maasvlakte, the Netherlands (51.59N,04.02E).
p3 shed 1
p2 shed 11
p1 shed 43
0 shed 145
n = 200.
two birds had p2 shed, while p1 was (almost) fully grown, hence followed a "condensed" moult strategy.

 

 U.K.: graellsii
adult LBBG in June, ringed in Britain. (61948 bytes)adult LBBG FA 8370?, June 02 2003, Papegaaienbek, Maasvlakte, the Netherlands. An adult ringed with a BTO ring: London FA 8370?.
adult LBBG in June, ringed in the U.K. (49422 bytes)adult LBBG GT 75716, June 02 2003, Papegaaienbek, Maasvlakte, the Netherlands. An adult ringed with a BTO ring: London GT 75716.
France: graellsii
Lesser Black-backed Gull 5cy 377NJune 23 2010, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull adult 989N June 19 2010, Calais, NW France. Picture: Jean-Michel Sauvage.
Lesser Black-backed Gull 8cy FRP EA639841 June 25 2012, Calais, NW France. Picture: Jean-Michel Sauvage.
Belgium: graellsii 'Dutch intergrade'
adult LBBG in June, ringed in Belgium. (74230 bytes)adult LBBG L 92594, June 17 2002, EMO - Maasvlakte, the Netherlands. An adult ringed with a Belgium ring, but mistake in reading code. In the colonies at the Maasvlakte different birds with British and Belgium rings are found breeding with local Dutch intergrades.
Lesser Black-backed Gull 6-8cy BLB L906179 2010-2012, Calais, NW France. Picture: Jean-Michel Sauvage.
adult LBBG in June, ringed in Belgium. (57581 bytes)adult LBBG ? ?9951, June 02 2003, Dintelhaven, Maasvlakte, the Netherlands. An adult ringed with a Belgium ring: Bruxelles ? -?9951.
the Netherlands: graellsii 'Dutch intergrade'
adult LBBG in June, ringed in the Netherlands. (75836 bytes)12cy LBBG K98, June 17 2002, Papegaaienbek - Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus, July 04 1991.
adult LBBG in June, ringed in the Netherlands. (68885 bytes)12cy LBBG T88, June 17 & 18 2002, Papegaaienbek - Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus, July 08 1991.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)8+cy LBBG FADU June 24 2011, Texel, the Netherlands. Ringed as breeding female.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)18cy LBBG FAHP June 24 2011, Texel, the Netherlands. Ringed as breeding female.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)6+cy LBBG FAHR June 24 2011, Texel, the Netherlands. Ringed as breeding female.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)5+cy LBBG FAKT June 24 2011, Texel, the Netherlands. Ringed as breeding female.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)5cy LBBG KLAS June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)6+cy LBBG MADB June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)15cy LBBG MAFZ June 24 2011, Texel, the Netherlands. Ringed as breeding female.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)7+cy LBBG MAKL June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)7+cy LBBG MAKR June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)5+cy LBBG MALZ June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)6+cy LBBG MAMP June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)6+cy LBBG MAMZ June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)4+cy LBBG MAPJ June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)4+cy LBBG MAPV June 24 2011, Texel, the Netherlands. Ringed as breeding male.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)adult LBBG MARS June 8 2012, Texel, the Netherlands. Ringed as breeding adult.
adult LBBG in June, ringed in the Netherlands. (57378 bytes)10cy LBBG CY5, June 17 2002, Papegaaienbek Maasvlakte, the Netherlands. Ringed June 18 1993. Head feather moult has started around the eye.
adult LBBG in June, ringed in the Netherlands. (62470 bytes)10cy LBBG MA9, June 17 2002, Papegaaienbek Maasvlakte, the Netherlands. Ringed July 01 1993.
adult LBBG in June, ringed in the Netherlands. (62054 bytes)adult LBBG NA1, June 17 2002, Papegaaienbek Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus. Still no primaries shed by mid June.
adult LBBG in June, ringed in the Netherlands. (72840 bytes)7cy LBBG PP4, June 02 2003, Dintelhaven Maasvlakte, the Netherlands. Ringed as pullus June 28 1997, now 7cy. Present from 2001.
adult LBBG in June, ringed in the Netherlands. (62058 bytes)adult LBBG TV4, June 18 2002, Dintelhaven Maasvlakte, the Netherlands. Ringed as pullus at the Maasvlakte.
adult LBBG in June, ringed in the Netherlands. (56483 bytes)10cy LBBG UX2, June 17 2002, Papegaaienbek Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus, June 21 1993.
1827er14.jpg (69521 bytes)8cy LBBG ER14, June 02 2003, Dintelhaven Maasvlakte, the Netherlands. Ringed as pullus June 26 1996, now 8cy.
adult LBBG in June, ringed in the Netherlands. (90222 bytes)8cy LBBG ES98, June 02 2003, Dintelhaven Maasvlakte, the Netherlands. Ringed as pullus June 26 1996, now 8cy.
adult LBBG in June, ringed in the Netherlands.6cy LBBG EU06, June 16 2001, Dintelhaven Maasvlakte, the Netherlands. Female, with dark iris, mated with adult male right. Ringed as pullus June 28 1996.
adult LBBG in June, ringed in the Netherlands. (49236 bytes)7cy LBBG EAS1, June 02 2003, Dintelhaven Maasvlakte, the Netherlands. Ringed as pullus June 24 1997, now 7cy.
mixed pair of michahellis x fuscusYLG (L. michahellis michahellis) 14+cy CU9 & adult LBBG, June 02 2003, Missouriweg - Maasvlakte, the Netherlands.
adult LBBG in June, ringed in the Netherlands.9cy LBBG KC9, June 17 2001, Missouriweg Maasvlakte, the Netherlands. Ringed July 07 1993.
adult LBBG in June, ringed in the Netherlands.9cy LBBG KH0, June 26 2001, Bergen op Zoom, the Netherlands. Ringed July 07 1993.
adult LBBG in June, ringed in the Netherlands. (41422 bytes)9cy LBBG E053, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed as pullus June 01 1995, now 9cy.
adult LBBG in June, ringed in the Netherlands.7cy LBBG E757,June 17 2001, Missouriweg Maasvlakte, the Netherlands. Ringed July 09 1995.
adult LBBG in June, ringed in the Netherlands.7cy LBBG E832, June 17 2001, Missouriweg Maasvlakte, the Netherlands. Ringed July 09 1995.
adult LBBG in June, ringed in the Netherlands.adult LBBG EC13, June 26 2001, Bergen op Zoom, the Netherlands.
adult LBBG in June, ringed in the Netherlands. (77018 bytes)8cy LBBG EK85, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed as pullus July 09 1996, now 8cy.
adult LBBG in June, ringed in the Netherlands. (70789 bytes)8cy LBBG EM30, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed as pullus July 10 1996, now 8cy.
adult LBBG in June, ringed in the Netherlands. (66296 bytes)6cy LBBG EY87, June 17 2002, EMO - Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus, July 03 1997.
adult LBBG in June, ringed in the Netherlands. (61343 bytes)6cy LBBG PL3, June 24 2002, Papegaaienbek - Maasvlakte, the Netherlands. Ringed at Maasvlakte as pullus, July 1997.
adult LBBG in June, ringed in the Netherlands. (70101 bytes)ad LBBG 5.251.194, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed with a Dutch ring: Arnhem Vogeltrekstation 5.251.194.
adult LBBG in June, ringed in the Netherlands. (61397 bytes)15cy LBBG 5.257.218, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed as pullus July 09 1989, now in 15cy with 3 pulli. Arnhem Vogeltrekstation 5.257.218.
adult LBBG in June, ringed in the Netherlands. (57024 bytes)15cy LBBG 5.257.580, June 02 2003, Missouriweg, Maasvlakte, the Netherlands. Ringed as pullus July 09 1989, now in 15cy. Ringed with a Dutch ring: Arnhem Vogeltrekstation 5.257.580.
adult LBBG in June, ringed in the Netherlands. (65264 bytes)ad LBBG 5.280.505, June 24 2002, Papegaaienbek - Maasvlakte, the Netherlands. Ringed with a Dutch ring: Arnhem Vogeltrekstation 5.280.505. A dark individual.
Denmark: intermedius
adult LBBG intermedius in September, ringed in Norway. (95609 bytes)LBBG VC5M June 18 2010, Hirsholm, Frederikshavn, Denmark (02 57.29N-010.38E). Pictures: Kjeld Tommy Pedersen.

Arrested & Suspended Moult in June adult LBBG
suspended moult in adult LBBG in June. (76647 bytes)adult LBBG, June 02 2003, Maasvlakte, the Netherlands. Active moult in both wings, replacing P7 & P8.