Moerdijk Field Research 2005-2006

(last update: 14 August 2010)
coordinators: 
Roland-Jan Buijs
Theo Muusse
Mars Muusse

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Introduction
Methods
Age, origin & sex
Retrapped Birds
Upperparts Greytone
Black on Primary Coverts
Black on Primaries
P10 and P9 Patterns
P5 Pattern
Red & Black on Bill
Iris & Orbital Ring
Primary Moult
Discussion
References

 Larus argentatus argenteus & Larus fuscus graellsii - Moerdijk, the Netherlands

P5 Primary Pattern

The P5 primary pattern was scored in five classes.
. I Complete sub-terminal band.
. II Sub-terminal band broken, but black on both webs.
. III Sub-terminal black present on one web, sharply defined.
. IV Sub-terminal black present on one web, diffuse marking.
. V No black present. For more details, see Goethe (1961).

The scores for sub-terminal black patterns on P5 are shown for both Herring and Lesser Black-backed Gulls in table 5.
Only 18% of Herring Gulls completely lacked black on P5, with most birds (32%) having a sharply defined black mark on the outer web. There was a significant difference between sexes in terms of the P5 scores, with males having higher values (more black) than females (Mann-Whitney U = 7406, Z = -3.136, P = 0.002, male n = 147, female n = 128). When sub-adult birds are excluded, the difference between the sexes remain significant (Mann-Whitney U = 6540, Z = -2.678, P = 0.007, male n = 130, female n = 124).

For P5 patterns too, it is interesting to compare retrapped Herring Gulls for 2005 and 2006. Twenty birds were retrapped, 12 remained in the same category, one bird showed more black in 2006 (HG m61) and seven birds showed less black.

About 95% of the Lesser Black-backed Gulls had a complete sub-terminal band on P5, and 5% had this black band broken at the shaft, resulting in two black markings on P5. Out of 967 Lesser Black-backed Gulls sampled, only one bird had no black on P5. There are no marked differences between sexes regarding the pattern on P5 (Mann-Whitney U = 106270, Z = -1.444, P = 0.149, male n = 436, female n = 498). When sub-adult birds are excluded, the difference between the sexes remains non-significant (Mann-Whitney U = 92291, Z = -1.386, P = 0.166, male n = 393, female n = 480).

Forty-three Lesser Black-backed Gulls were caught in both 2005 and 2006. Thirty-seven birds remained in the same category, one bird showed more black in 2006 (LBBG oSE) and one birds showed less black (LBBG m53).

P5 pattern total
I
II
III
IV
V
HG
12
21
32
15
18
287
HG, sub-adults excluded
12
22
32
15
19
265
LBBG
95
5
.
0
0
967
LBBG, sub-adults excluded
94
5
.
0
0
905

Table 5: P5 primary pattern of Herring and Lesser Black-backed Gull at Moerdijk. Values are %. I: Complete sub-terminal band. II: Sub-terminal band broken, but black on both webs. III: Sub-terminal black present on one web, sharply defined. IV: Sub-terminal black present on one web, diffuse marking. V: No black present.

Read further on RESULTS: 6. RED & BLACK ON THE BILL >

 Herring Gull P5 primary pattern I: Complete sub-terminal band.
Herring Gull L.a. argenteus 7cy 4T, 16 May 2005.
Herring Gull L.a. argenteus 9cy P3, 16 May 2005.
Herring Gull L.a. argenteus 9cy LN, 13 May 2006.
Herring Gull P5 primary pattern II: Sub-terminal band broken, but black on both webs.
Herring Gull L.a. argenteus 8cy 2Z, 06 May 2005.
Herring Gull L.a. argenteus 11cy H2, 05 May 2006.
Herring Gull L.a. argenteus 14cy & 15cy VE, 21 May 2005 & 16 May 2006. Scoring II in 2006, but scoring I in 2005.
Herring Gull P5 primary pattern III: Sub-terminal black present on one web, sharply defined.
Herring Gull L.a. argenteus 8cy 59, 21 May 2005.
Herring Gull L.a. argenteus 13cy 10, 05 May 2005.
Herring Gull L.a. argenteus 24cy PL, 07 May 2006.
Herring Gull P5 primary pattern IV: Sub-terminal black present on one web, diffuse marking.
Herring Gull L.a. argenteus 7cy 3E, 14 May 2005.
Herring Gull L.a. argenteus 14cy C0, 06 May 2005.
Herring Gull L.a. argenteus 19cy S0, 06 May 2005.
Herring Gull P5 primary pattern V: No black present.
Herring Gull L.a. argenteus 10cy KL, 09 May 2006.
Herring Gull L.a. argenteus 11cy JK, 06 May 2006.
Herring Gull L.a. argenteus 17cy 1A, 04 May 2005.
Lesser Black-backed Gull P5 primary pattern I: Complete sub-terminal band.
Lesser Black-backed Gull L.f. graellsii 14cy C5, 08 May 2006.
Lesser Black-backed Gull L.f. graellsii 14cy UX, 15 May 2006.
Lesser Black-backed Gull L.f. graellsii 14cy ST, 21 May 2005.
Lesser Black-backed Gull P5 primary pattern II: Sub-terminal band broken, but black on both webs.
Lesser Black-backed Gull L.f. graellsii 8cy 6W, 09 May 2006.
Lesser Black-backed Gull L.f. graellsii 11cy K9, 16 May 2005.
Lesser Black-backed Gull L.f. graellsii 13cy CK, 06 May 2005.
Lesser Black-backed Gull P5 primary pattern III: Sub-terminal black present on one web, sharply defined.
No such birds in our sample.
Lesser Black-backed Gull P5 primary pattern IV: Sub-terminal black present on one web, diffuse marking.
Lesser Black-backed Gull L.f. graellsii PT, 16 May 2006. Single bird scoring IV.
Lesser Black-backed Gull P5 primary pattern V: No black present.
Lesser Black-backed Gull L.f. graellsii 4W, 08 May 2006. Single bird scoring V.