Table 6: Characteristics of Perched First-years by Location for Atlantic Yellow-legged Gull

Area

Month

Mantle colour

Mantle texture

Bill colour

Tertials

 

 

S

RB

RT

GB

S

SC

LC

S

BL

PB

S

PF

PT

PC

PN

San Sebastian

February

8

25

50

25

2

100

0

9

65

35

2

100

0

0

0

Santander

August

16

25

60

15

8

55

45

5

20

80

1

0

0

100

0

Porto/

Minho

April

82

+

85

15

63

90

10

73

75

25

29

80

20

0

0

Lisbon

May

17

15

70

15

15

50

50

25

80

20

7

100

0

0

0

Setubal

March

2

0

0

100

1

0

100

2

100

0

0

 

 

 

 

Faro

March

17

0

25

75

12

90

10

19

85

15

6

100

0

0

0

Nerja

May

7

0

15

85

4

75

25

4

100

0

0

 

 

 

 

Estepona

August

6

0

15

85

2

0

100

3

100

0

4

75

0

0

25

Gibraltar/ La Linea

August

27

0

95

5

18

10

90

17

100

0

15

55

20

5

20

Tanger

August

68

5

45

50

24

50

50

23

95

5

4

0

100

0

0

Asilah

August

3

0

35

65

3

35

65

2

100

0

0

 

 

 

 

Agadir/

Essaouira

April

60

10

40

50

13

55

45

46

80

20

7

85

15

0

0

Lanzarote

August

22

0

20

80

16

55

45

15

100

0

2

100

0

0

0

Fuerte-ventura

April

28

0

55

45

18

70

30

17

75

25

5

100

0

0

0

Septem-ber

9

0

55

45

4

50

50

9

100

0

0

 

 

 

 

Gran Canaria

May

22

15

50

35

4

75

25

20

45

55

3

35

65

0

0

Septem-ber

22

10

20

70

8

100

0

10

100

0

8

100

0

0

0

Tenerife

July

48

0

5

95

14

30

70

24

100

0

3

65

35

0

0

August

41

0

20

80

14

30

70

17

90

10

6

100

0

0

0

La Palma/ El Hierro

August

8

0

0

100

3

35

65

7

100

0

4

75

25

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Canta-brican

 

24

25

57

18

10

68

32

14

50

50

3

67

0

33

0

W Portugal/ NW Spain cline

 

101

5

80

15

79

83

17

100

77

23

36

83

17

0

0

Dark

 

280

4

29

67

109

58

42

186

85

15

44

86

14

 

0

Med. Inter-section

 

108

3

53

44

48

35

65

47

98

2

23

48

31

4

17

All forms

 

513

5

45

50

246

62

38

347

83

17

106

76

18

2

4

   

From analysis of close-up photographs and field study as in Table 2. Data for San Sebastian from photographs of Dick Newell (2000) at Dick Newell's section on Cantabrican Yellow-legged Gulls on Martin Reid's site .

Percentages are rounded to nearest 5 for individual localities. Cantabrican, W Portugal/NW Spain cline, Dark form and Mediterranean intersection are defined in the text.

+ -- noted but less than 3%.

Key: S Sample size;

Mantle colour: RB Ruddy Brown as in some worn michahellis; RT Ruddy Tinge to grey-brown as in michahellis or argenteus; GB Grey-Brown as in graellsii;

Mantle texture: SC Scaley as in marinus; LC Less contrasting as in graellsii/argenteus;

Bill colour: BL all-black as in graellsii; PB black with pale base as in argenteus; birds categorised as PB if base is pale to any extent.

Tertials: PF narrow pale fringe around grey-brown centre as in graellsii; PT large pale tip and narrow pale fringe to dark grey-brown or rusty-brown centre; PC large pale tip and fringe with pale internal markings as in some argenteus; PN narrow pale fringe with slight notching on each sides of feather.

Table 7: Characteristics of First-years in Flight by Location for Atlantic Yellow-legged Gull

Area

Month

Underwing Pattern

Tail colour

Inner wing

Pale primary panel

 

 

S

UN

CS

CM

S

BR

DL

S

2B

1B

S

OB

IN

NO

San Sebastian

February

4

0

100

0

6

15

85

6

15

85

8

50

50

0

Santander

August

0

 

 

 

1

100

0

2

0

100

2

50

50

0

Porto/Minho

April

23

45

50

5

33

25

75

25

10

90

28

35

45

20

Lisbon

May

4

0

100

0

15

95

5

17

30

70

5

45

35

20

Setubal

March

1

0

0

100

0

 

 

0

 

 

2

0

100

0

Faro

March

12

20

40

40

6

85

15

5

80

20

13

15

45

40

Nerja

May

0

 

 

 

3

100

0

3

0

100

3

35

65

0

Estepona

August

2

0

100

0

16

95

5

3

0

100

3

35

35

30

Gibraltar/La Linea

August

3

0

65

35

8

100

0

0

0

100

7

0

70

30

Tanger

August

11

30

55

15

20

80

20

10

40

60

18

10

65

25

Asilah

August

2

0

100

0

3

65

35

2

50

50

3

0

65

35

Agadir/

Essaouira

April

45

40

55

5

24

75

25

6

50

50

48

35

50

15

Lanzarote

August

3

0

100

0

1

100

0

1

0

100

3

20

20

60

Fuerteventura

April

5

40

20

40

19

95

5

7

30

70

20

20

65

15

Septem-ber

9

10

90

0

6

100

0

3

35

65

11

20

60

20

Gran Canaria

May

19

65

30

5

8

90

10

2

0

100

17

60

20

20

Septem-ber

14

35

35

30

9

90

10

6

35

65

16

45

30

25

Tenerife

July

11

20

45

35

46

90

10

4

50

50

25

0

80

20

August

12

20

45

35

12

90

10

6

60

40

14

10

75

15

La Palma/ El Hierro

August

3

0

0

100

7

70

30

2

0

100

4

0

50

50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Canta-brican

 

4

0

100

0

7

29

71

8

12

88

10

50

50

0

W Portugal/ NW Spain cline

 

28

36

57

7

48

48

52

42

17

83

35

35

45

20

Dark

 

135

33

48

19

141

87

13

44

43

57

174

25

53

22

Med. Inter-section

 

16

19

63

18

47

89

11

25

17

83

31

13

64

23

All forms

 

183

32

52

16

243

78

22

119

26

74

250

26

53

21

   

From analysis of close-up photographs and field study as in Table 2. Data for San Sebastian from photographs of Dick Newell (2000) at Dick Newell's section on Cantabrican Yellow-legged Gulls on Martin Reid's site .

Percentages are rounded to nearest 5 for individual localities. Cantabrican, W Portugal/NW Spain cline, Dark form and Mediterranean intersection are defined in the text.

Key: S Sample size;

Underwing pattern: UN Uniform as in graellsii; CS some contrast between coverts and outer wing as in michahellis or marinus; CM marked contrast;

Tail colour: BR Bright as in graellsii; DL Dull as in argenteus; birds categorised as BR if tail gleams significantly and only a small number of dark flecks cover the pale area.

Inner wing: 2B two bars present as in graellsii; 1B one bar present as in argenteus; birds categorised as 2B if the greater coverts bar is obvious in flight.

Pale primary panel: OB Obvious as in argenteus; IN indistinct as in michahellis; NO None as in graellsii; birds categorised, seen from below, as OB if pale primary panel is a striking feature and as IN if the pale area is present but needs to be searched for; from above, where this feature is less easy to view, OB would indicate a clear pale area and IN a palish area compared to the surrounding area; in both cases NO indicates no trace of a pale area.

 

Table 8: Head and Body Streaking in First-year Atlantic Yellow-legged Gulls at Particular Locations

Location

Dates visited

Juvenile/1st-year Head markings

Juvenile/1st-year Breast markings

Juvenile/1st-year Belly markings

 

 

S

dusky

white

S

heavy

sparse

white

S

heavy

sparse

white

San Sebastian

February

10

90

10

5

60

40

0

5

60

40

0

Santander

1 - 9 Aug

16

100

0

10

90

10

0

10

90

10

0

Porto/

Minho

29 Mar-4 Apr

64

70

30

62

55

40

5

62

55

40

5

Lisbon

13 - 16 May

31

75

25

5

20

20

60

5

20

80

0

Setubal

27 - 29 Mar

4

75

25

3

65

35

0

3

100

0

0

Faro

25 - 31 Mar

25

70

30

10

50

50

0

10

40

60

0

Nerja

26 - 31 May

4

0

100

3

0

0

100

3

0

0

100

Estepona

17 Aug

4

100

0

3

100

0

0

1

0

100

0

Gibraltar/

La Linea

22 Aug

26

75

25

21

40

55

5

19

35

55

10

Tanger

10 - 17 Aug

92

80

20

16

55

40

5

17

60

35

5

20 Aug

27 Aug-2 Sept

Asilah

20 - 27 Aug

23

75

25

3

100

0

0

3

100

0

0

Agadir/ Essaouira

12 - 18 Apr

52

90

10

21

20

65

15

23

20

70

10

23 - 30 Apr

Lanzarote

13 -2 0 Aug

31

95

5

4

100

0

0

4

100

0

0

Fuerte-ventura

7 - 14 Apr

22

80

20

10

80

20

0

10

80

20

0

29 Sept

8

100

0

7

85

15

0

6

85

15

0

Gran Canaria

14 - 20 May

18

70

30

15

25

70

5

15

25

70

5

23 - 30 Sept

17

95

5

15

80

20

0

15

55

40

5

Tenerife

28 Jul-10 Aug

28

95

5

18

90

5

5

18

55

45

0

4 - 18 Aug

39

80

20

5

80

20

0

5

80

20

0

La Palma/El Hierro

5 - 9 Aug

7

85

15

4

100

0

0

4

100

0

0

Canta-brican

 

26

96

4

15

80

20

0

15

80

20

0

W Portugal/ NW Spain cline

 

99

71

29

70

54

39

7

70

54

39

7

Dark

 

270

85

15

112

62

33

5

113

52

44

4

Med. Inter-section

 

130

77

23

43

46

42

12

40

42

42

16

All forms

 

525

81

19

240

58

36

6

238

53

41

6

   

From an analysis of close-up photographs and from field study by the author as in Table 2. Data for San Sebastian from photographs of Dick Newell (2000) at Dick Newell's section on Cantabrican Yellow-legged Gulls on Martin Reid's site .

Percentages are rounded to nearest 5 for individual localities. Cantabrican, W Portugal/NW Spain cline, Dark form and Mediterranean intersection are defined in the text.

Key: S Sample size;

Head markings: Dusky as in argenteus; White, except for dark eye spot, as in Mediterranean michahellis; birds categorised as DS, if as well as the dusky eye spot, there is at least an extensive dusky wash over the back of the head, the sides of the head and the loral area.

Breast and Belly Streakings: Heavy as in graellsii; Sparse as in Mediterranean michahellis; White as in bleached Mediterranean michahellis.