Adult Herring Gull with Thayeri pattern on P9 – 20130803

This is my 100th blog post, and it nicely links to my very first post back in October 2011…

This European Herring Gull Larus argentatus caught my eye today because of the bare patches on the head, thereby possibly indicating its old age.

Adult European Herring Gull with bare patches on the head. Leiden, 3 August 2013.

Adult European Herring Gull with bare patches on the head. Leiden, 3 August 2013.

After studying the photos at home I noticed that primary P9 is showing a Thayeri pattern: the grey tongue joins the mirror and as a result the black never reaches the edge of the inner web. This pattern is not rare in European Herring Gulls but is more commonly seen in Scandinavian Herring Gulls Larus argentatus argentatus (see for instance White KH89, the topic of my very first blog post).

Adult European Herring Gull with a Thayeri pattern on P9. Leiden, 3 August 2013.

Adult European Herring Gull with a Thayeri pattern on P9. Leiden, 3 August 2013.

It turns out that this gull is even more distinctive because it is missing its left foot. All in all, it should not be difficult to recognize this individual on future occasions…

Adult European Herring Gull with a Thayeri pattern on P9 and a missing left foot. Leiden, 3 August 2013.

Adult European Herring Gull with a Thayeri pattern on P9 and a missing left foot. Leiden, 3 August 2013.

References

Phenotypic characteristics and moult commencement in breeding Dutch Herring Gulls Larus argentatus & Lesser Black-Backed Gulls L. fuscus

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3 thoughts on “Adult Herring Gull with Thayeri pattern on P9 – 20130803

  1. Another thought with regard to gulls with bare patches… have you ever heard of Psittacine Beak And Feather Disease? It’s a nasty, degenerative viral condition in parrots (I suppose that it’s the closest that they have to a disease like HIV-AIDS – one that gradually rots you away) that first visibly manifests itself with feather loss, similar to that seen in the gulls you’ve photographed. Is there an equivalent to this disease in gulls, do you know?

      • I saw the first picture in your post and the resemblance was striking!

        That said, its head also looks a lot like a Cockatiel I once knew that used to get into (and lose) a lot of fights over other birds’ nestboxes…

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