Just for fun: comparison of the primary pattern of 6 different adult Common Gulls Larus canus canus.
Each photo shows the wing of a different individual. The photos were taken during ringing activities in Zaandam, the Netherlands, 2018.
Click for a larger view.
Note the following differences in the pattern of each feather:
- P10: the white of the mirror on the outer web sometimes reaches the tip.
- P9: mirror is larger than subterminal band, black on outer web reaches primary coverts.
- P8: no mirror, length of black on outer web ranges between <1/3 and >1/3 to 1/2.
- P7: length of black on outer web ranges between <1/2, 1/2 and >1/2.
- P6: length of black on outer web is <1/3.
- P5: pattern ranges from a full band to a broken band and black on only the inner web.
- P4: no black.
References: Adriaens P. Gibbins C., 2016. Identification of the Larus canus complex, Dutch Birding, Volume 38(1).