Primary pattern variation in individual European Herring Gull – 2015 update

For the 7th year in a row, I have been able to analyze the primary pattern of an adult European Herring Gull which I observe on a regular basis each year.

It was fitted with color rings in 1986 when it was a juvenile and subsequently re-ringed in 2015. In a few months time it will be 29 years old.

ZDGA-FAMA-20150307-1

European Herring Gull Green FAMA, formerly known as ZDGA. Leiden, the Netherlands, 7 March 2015.

I decided to compare the primary pattern a few years ago to see if there were any yearly changes to be seen, and indeed this was the case (see the blog post of 2013 and that of 2014).

In March and April 2015 I was able to make the first clear images of FAMA’s current moult cycle so it is time to compare the pattern with that of previous years.

Here are the results (click on the images for a larger view):

Left wing

ZDGA_primary_pattern_left_wing

P10: The shape and size of the mirror seems to be the same as all previous years.
P9: Small mirror on the inner web only.
P8: The demarcation between the black and the grey tongue is a straight line (not curved upwards as last year).
P7: No major change.
P6: No major change.
P5: No black.

Right wing

ZDGA-FAMA-primary-pattern-right-wing-2009-2015

P10: The shape and size of the mirror seems to be the same as all previous years (with the exception of 2013).
P9: No mirrors.
P8: The demarcation between the black and the grey tongue is angled upwards.
P7: No major change.
P6: No major change.
P5: No black.

Summary

The following features stand out:

  • The shape of the mirror on P10 seems very consistant across all years.
  • The presence of black on P5 and that of mirrors on P9 is inconsistant for each year.

Here’s an overview of the pattern of the mirrors on P9:

Calendar year* Left wing Right wing
24th
Outer web only
None present
25th
None present
Inner web only
26th
Inner web only
Inner web only
27th
Inner web only
Inner and outer web
28th
Inner web only
Inner and outer web
29th
Outer web only
Inner and outer web
30th
Inner web only
None present

* The calendar years actually represent the moult cycle that was completed at the end of the previous calendar year; I’ve decided to refer to calendar years instead of moult cycles (in the 29th calendar year the 28th moult cycle was scored) for readability reasons.

Here’s an overview of the presence of black on P5:

Calendar year* Left wing Right wing
24th
Outer web only
Outer web only
25th
Outer web only
Outer web only
26th
Outer web only
Outer web only
27th
Outer web only
Outer web only
28th
Outer web only
Outer web only
29th
Outer web only
None present
30th
None present
None present

* The calendar years actually represent the moult cycle that was completed at the end of the previous calendar year; I’ve decided to refer to calendar years instead of moult cycles (in the 29th calendar year the 28th moult cycle was scored) for readability reasons.

That’s it for this year, here’s hoping that she is still around next year for another comparison.

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