Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

Herring Gull adults September

Introduction

This website deals with the Herring Gulls of the taxa argentatus and argenteus. Argenteus is an abundant breeding species on Iceland, Britain, NW France, Belgium, the Netherlands and N Germany. The taxon argentatus breeds in NE Europe, from Denmark, the coast of the Baltic Sea, Scandinavia and coast of the White Sea. In the centre of the breeding range (Denmark and the NW German coast), birds show intermediate characteristics, indicating there is a cline in argenteus-argentatus. Argenteus in Western Europe is pale-backed, slightly smaller and with relatively much black in the wing-tip; argentatus in the NE Europe is larger, slightly darker on upper-parts and show less black in the wing-tip.
Due to the large breeding range, there is much intra-specific variation in argentatus, with most large, powerful birds in the northern populations, showing the most darkest upper-parts, longest wing and most white in the outer-wing. In this region, some populations may hold substantial number of yellow-legged argentatus. (referred to as "Finnmark yellow-legged argentatus"). In adult plumage, the black sub-terminal spot on P5 is often lacking or strongly reduced to a diffuse streak, broken at the centre. Sometimes P6 lacks black as well. 
In the Baltic region, other yellow-legged argentatus populations occur ("Baltic yellow-legged argentatus"), with adults showing even brighter yellow legs in summer and the upper-parts only slightly darker than West European argenteus, still much paler than Yellow-legged Gull (michahellis). Those Baltic argentatus often show a black sub-terminal spot on P5 in adult plumage.
On these web-pages, we largely follow P.J. Grant: "Gulls, a guide to identification" and E.K Barth's publication as Contribution No. 86, Zoological Museum, University of Oslo: "The circumpolar systematics of Larus argentatus and Larus fuscus with special reference to the Norwegian populations".

adult Herring Gull in September

Adults are in active moult. Simultaneously,most birds are in the last phase of the wing-covert moult: the central greater coverts and lesser coverts are replaced.

Tables & Graph

remaining AUTUMN

 

 

 

 

 

 

 

 

 

starting date:

13 Aug

20 Aug

27 Aug

03 Sep

10 Sep

17 Sep

01 Oct

15 Oct

05 Nov

12 Nov

week no:

33

34

35

36

37

38

40

42

45

46

0

0

0

0

0

 

4

170

54

32

105

1

0

0

1

6

 

13

24

10

1

1

2

0

3

22

35

1

4

9

2

 

 

3

9

71

103

63

 

1

 

1

 

 

4

30

99

34

4

 

0

 

 

 

 

5

11

29

5

0

 

0

 

 

 

 

6

0

0

0

0

 

0

 

 

 

 

7

0

0

0

0

 

0

 

 

 

 

8

0

0

0

0

 

0

 

 

 

 

9

0

0

0

0

 

0

 

 

 

 

10

0

0

0

0

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

n=

50

202

165

108

1

22

203

67

33

106

average REM P:

4.0

3.8

3.1

2.6

2.0

1.1

0.2

0.3

0.0

0.0

95% CID =

0.18

0.10

0.11

0.12

 

0.33

0.07

0.14

0.06

0.02

inverse =

2.01

1.97

1.97

1.98

 

2.08

1.97

2.00

2.04

1.98

Variantie (s2) =

0.41

0.50

0.47

0.43

 

0.56

0.25

0.34

0.03

0.01

SD (s) =

0.64

0.71

0.69

0.65

 

0.75

0.50

0.59

0.17

0.10

SE (sx) =

0.09

0.05

0.05

0.06

 

0.16

0.04

0.07

0.03

0.01

 

 

 

 

 

 

 

 

 

 

 

% class:

 

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

18

84

81

97

99

1

0

0

1

6

0

59

12

15

3

1

2

0

1

13

32

100

18

4

3

0

0

3

18

35

62

58

0

5

0

1

0

0

4

60

49

21

4

0

0

0

0

0

0

5

22

14

3

0

0

0

0

0

0

0

6

0

0

0

0

0

0

0

0

0

0

7

0

0

0

0

0

0

0

0

0

0

8

0

0

0

0

0

0

0

0

0

0

9

0

0

0

0

0

0

0

0

0

0

10

0

0

0

0

0

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

 

% control:

100

100

100

100

100

100

100

100

100

100

  Table above, data for the Netherlands (2000-2010), results for spring & summer (aggregated week): number of remaining old primaries in adults.
0 = 0 old primaries left (P10 dropped); 10 = all 10 primaries still old and present.

Above: Scatter Plot for PMS in adult Herring Gulls. Number of remaining old primaries throughout the year. Sample size is 1.329 birds.

new: AUTUMN

 

 

 

 

 

 

 

 

 

 

 

 

starting date:

17 Sep

24 Sep

01 Oct

08 Oct

15 Oct

22 Oct

29 Oct

05 Nov

12 Nov

19 Nov

26 Nov

03 Dec

week no:

38

39

40

41

42

43

44

45

46

47

48

49

0

0

0

0

0

0

 

 

0

0

 

0

 

1

0

0

0

0

0

 

 

0

0

 

0

 

2

3

0

0

0

0

 

 

0

0

 

0

 

3

1

0

0

0

0

 

 

0

0

 

0

 

4

10

0

0

0

0

 

 

0

0

 

0

 

5

98

26

2

1

1

 

 

0

0

 

0

 

6

138

100

127

9

4

 

1

0

0

 

0

 

7

44

55

391

175

65

24

10

2

20

 

0

 

8

6

1

104

98

83

87

71

54

222

31

20

2

9

0

0

3

4

4

18

23

49

256

60

76

13

10

0

0

0

0

0

 

3

15

39

36

222

59

 

 

 

 

 

 

 

 

 

 

 

 

 

n=

300

182

627

287

157

129

108

120

537

127

318

74

average NEW P:

5.7

6.2

7.0

7.3

7.5

8.0

8.2

8.6

8.6

9.0

9.6

9.8

95% CID =

0.10

0.10

0.05

0.07

0.10

0.10

0.13

0.13

0.06

0.13

0.07

0.11

inverse =

1.97

1.97

1.96

1.97

1.98

1.98

1.98

1.98

1.96

1.98

1.97

1.99

Variantie (s2) =

0.81

0.44

0.40

0.33

0.39

0.33

0.43

0.52

0.46

0.53

0.36

0.23

SD (s) =

0.90

0.66

0.63

0.58

0.63

0.57

0.66

0.72

0.68

0.73

0.60

0.48

SE (sx) =

0.05

0.05

0.03

0.03

0.05

0.05

0.06

0.07

0.03

0.06

0.03

0.06

 

 

 

 

 

 

 

 

 

 

 

 

 

% class:

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

0

0

0

0

2

1

0

0

0

0

0

0

0

0

0

0

0

3

0

0

0

0

0

0

0

0

0

0

0

0

4

3

0

0

0

0

0

0

0

0

0

0

0

5

33

14

0

0

1

0

0

0

0

0

0

0

6

46

55

20

3

3

0

1

0

0

0

0

0

7

15

30

62

61

41

19

9

2

4

0

0

0

8

2

1

17

34

53

67

66

45

41

24

6

3

9

0

0

0

1

3

14

21

41

48

47

24

18

10

0

0

0

0

0

0

3

13

7

28

70

80

 

 

 

 

 

 

 

 

 

 

 

 

 

% control:

100

100

100

100

100

100

100

100

100

100

100

100

Table above, data for the Netherlands (2000-2010), results for autumn & winter (aggregated week): number of new, fully grown primaries in adults.
0 = no new primaries visible. So either P1 still old, or P1 dropped, but the very tip still not visible.
1 = P1 longest new primary. Range between "at least the tip of P1 is visible" until "tip of P2 still shorter than P1".
2 = P2 longest new primary. 3 = etc.

Above: Scatter Plot for PMS in adult Herring Gulls throughout the year. Longest new primary is classified "fully grown". Sample size is 3.271 birds. Birds scored on NEW primaries.

The first date in our analysis on adult Herring Gulls is 02 May 2006 (week 18 - starting 30 April), on which we already found birds with missing primaries (some birds had already shed 3 primaries). This group of actively moulting birds, 43% of the sample, must have started the complete moult somewhere around mid-April and probably several birds may have started earlier.

The last scoring day has been 03 December, when still 20% of the sampled birds had to grow P10. The final stage of the complete moult for all birds has to be somewhere after mid-December. On 03 December we scored 59 birds with P10 fully grown, 13 birds with P9 fully grown and 2 birds with P8 fully grown. They all had no old primaries left.

The first time a new primary (P1) was visible, was also on 02 May 2006 (week 18 - starting 30 April). In this week, 90% of the sample did not show new primaries, but 9% did. Four birds in the sample of 115 birds alreday had P2 as longest primary (fully grown). As soon as the tip of P1 was visible, this was automatically scored "fully grown", and this was the case in 7 birds. 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).

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 = 1329, R2= 0.935, sign: P<0,000)
PMS = -0,379* WEEK + 16,324.

LINEAR REGRESSION FOR NEW FULLY GROWN PRIMARIES

Complete sample: Linear regression (n = 3271 R2= 0.927, sign: P<0,000)
PMS = 0,322* WEEK - 6,071.

rings argenteus: France
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull EA592432 adult (argenteus), September 16 2009, Boulogne/Mer, France. Picture: J-M Sauvage.
rings argenteus: Belgium
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull AJAT 13cy (argenteus), September 20 2011, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull CAAX 12cy (argenteus), September 21 2011, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull CTAZ 4+cy (argenteus), September 20-21 2010, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull CZAN 4+cy (argenteus), September 20 2009, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull CZAS 4+cy (argenteus), September 2009 & 2011, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull FCAR 6cy (argenteus), September 11 2011, Boulogne/Mer, France. Picture: J-M Sauvage.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull GAAJ 4+cy (argenteus), September 20 2009, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull GAAY 4+cy (argenteus), September 20 2011, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull GCAP 4+cy (argenteus), September 2009 & 2010, Westkapelle, Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull KPAV 12cy (argenteus), September 20 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull (argenteus) adult BLB H-47720 2009-2013, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-50949 12+cy (argenteus), 2010-2011, Leiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull L-102351 adult (argenteus), September 30 2010, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-127051 adult (argenteus), September 25 2012, Katwijk, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-131099 9cy (argenteus), September 16 2011, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage. Also as 6cy.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-132415 7cy (argenteus), September 30 2010, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-136798 adult (argenteus), September 03 2011, IJmuiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-137233 adult (argenteus), August & September 2012, Katwijk, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-1512x xadult (argenteus), September 22 2011, Westkapelle, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-151443 6+cy (argenteus), September 21 2011, Westkapelle, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-153256 adult (argenteus), September 25 & 28 2012, Katwijk, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-152381 adult (argenteus), September 20 2011, Westkapelle, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull (argenteus) adult BLB H-167641 September 13 2013, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull L-99798 11-12cy (argenteus), 2011-2012, IJmuiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull H-xxxxxx adult (argenteus), September 05 2009, IJmuiden, the Netherlands. Yellowish legs.
rings argenteus: the Netherlands
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.ACL 6+cy (argenteus), August-September 2010, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.ACL 4+cy (argenteus), September 05 2010, IJmuiden, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) adult MAPB September 17 2013, Katwijk, the Netherlands.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull DA 24-27cy (argenteus, 2009-2010, Leiden, Netherlands.
adult argenteus in September, ringed in the Netherlands. (52908 bytes)Herring Gull adult (argenteus) SA September 24 2002 & September 26 2003, IJmuiden, the Netherlands (52.27N 04.33E).
adult argenteus in September, ringed in the Netherlands. (47932 bytes)Herring Gull adult (argenteus) 7--, September 22 2003, IJmuiden, the Netherlands (52.27N - 04.33E).
adult argenteus in September, ringed in the Netherlands. (85378 bytes)Herring Gull adult (argenteus) S---, September 26 2003, IJmuiden, the Netherlands (52.27N - 04.33E).
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) adult BT September 19 2013, Katwijk, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull E2 adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull EN adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull A4 adult (argenteus), September 20 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull AA adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull AC adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull H1 adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull JA adult (argenteus), September 24 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull JZ adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull K9 adult (argenteus), September 19 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull MK adult (argenteus), September 24 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull PJ adult (argenteus), September 22 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull RJ adult (argenteus), September 2009 & 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull S7 adult (argenteus), September 20 2011, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull SD adult (argenteus), September 20 2011, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 3V adult (argenteus), September 22 2010, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 49 adult (argenteus), September 21 2009, Westkapelle, Netherlands.
adult argenteus in October, ringed in the Netherlands. (35116 bytes)Herring Gull 65 adult (argenteus), September 24 2009, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.AFL adult (argenteus), March 2010 & September 2011, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.AFM adult (argenteus), September 23 2010, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.ASD adult (argenteus), September 23 2010, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull M.ABB adult (argenteus), August-September 2011, Leiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull M.ABK adult (argenteus), September 21 2010, Westkapelle, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull E096 adult (argenteus), September 05 2010, IJmuiden, Netherlands. Picture: M v Kleinwee.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull NLA.5.425.481 4+cy (argenteus), September 2011 - January 2012, IJmuiden, the Netherlands.
adult argenteus in September, ringed in the Netherlands. (95123 bytes)Herring Gull 11cy (argenteus) 5.293.863 September 21 2004, Scheveningen, the Netherlands.
2cy argentatus in November. (81321 bytes)Herring Gull 11cy 5.352.700 (argenteus), September 23 2011, Scheveningen, the Netherlands.
adult argenteus in September, ringed in the Netherlands. (85715 bytes)Herring Gull adult (argenteus) 5.360.695 September 18 2004, IJmuiden, the Netherlands (52.27N 04.33E).
adult argenteus in September, ringed in the Netherlands. (38722 bytes)Herring Gull 10+cy (argenteus) 5.362.516 September 01 2006, IJmuiden, the Netherlands (52.27N 04.33E).
adult argenteus in September, ringed in the Netherlands. (38722 bytes)Herring Gull 9+cy (argenteus) 5.369.341 September 19 2008, IJmuiden, the Netherlands (52.27N 04.33E).
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 6.126.721 5cy (argenteus), September 03 2011, IJmuiden, the Netherlands.
adult argenteus in September, ringed in the Netherlands. (70332 bytes)Herring Gull adult (argenteus) 5.157.xxx, September 24 2002, Scheveningen, the Netherlands. A bird with yellowish legs.
adult argenteus in September, ringed in the Netherlands. (38722 bytes)Herring Gull adult (argenteus) 5.360.???, September 24 2002, IJmuiden, the Netherlands (52.27N 04.33E).
rings argentatus: Germany
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull AB97 9cy (argentatus), September 25 2009, Barneveld, the Netherlands.
unringed adult Herring Gulls
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull adult, September 12 2012, IJmuiden, the Netherlands.
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull adult, September 12 2012, IJmuiden, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) adult, September 19 2013, Katwijk, the Netherlands.
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull adult, September 12 2012, IJmuiden, the Netherlands.