Possible Kamchatka Gull in CA (1 Viewer)

[markseth]

So I know this is a long shot but...while birding today in Jenner CA I noticed a "biggish" Mew Gull. I watched it for a while and noted a sloping forehead and a bigger then normal bill. A wave came in and I got some flight photos. Not the best. Now I love birding but I don't entirely have the lingo down. Mirrors and tounge and stuff like that I'm still learning..lol. but I didn't notice that P8 was almost completely black which appears to be a key feature in identifying Kamchatka Gull from the more common brachyrhynchus Mew Gull. I read this article http://gull-research.org/papers/papers8/2016CommonGulls_AdriaensGibbins.pdf and attempted to follow the table laid out for identification. It was somewhat difficult and I am unsure if my photos are good enough to ID the bird from the primaries. I do believe using the article and table points to Kamchatka, but I'm not totally certain. Was looking for some help here. Thanks!!

 

[Brian J Small]

Whilst I do not have the same expertise as Smiths (as PA is known on BF), I have spent more time than is healthy looking at Common/Mew Gulls - largely from a NW European perspective.

I have annotated one of your images to show some of the features I can see and this may be helpful, but what I have learned - especially recently as we have 1000s of Common Gulls about the coast where I live - is that the features you hope will help can be a little more variable than (and not quite as clear cut as) you would like.

I am not quite sure what you mean when you describe P8 as being 'almost completely black' - the outer primary (P10) is almost completely black; the P8 pattern is interesting in that from above it seems to have a grey tongue (lacking the white tongue is more typical of brachyrhynchus); the black band on P5 is complete, whilst P4 lacks any black; the trailing edge is broadly white. These - reading Adriaens and Gibbins - are indicative of kamtschatschensis, but are they outside the variability of brachyrhynchus? I am not sure and herein lies the problem.

As an example, in a flock of 750 adult Common Gulls canus, I recently looked for white headed birds, finding 4 without any streaks or a few limited to the rear of the neck. This would indicate that they might be Russian Common heinei, but in flight only one of them had a wing tip pattern that was a little like heinei, with black on both webs of P4 - the other three had wing patterns identical to all the other canus.

Other questions you might ask: is the bill strong enough for kamtschatschensis? What did it look like like standing? It obviously caught your eye and I hope Smiths might give you more help than I have.

A very interesting bird, but I suspect within the range of variability shown by brachyrhynchus.

Brian S

 

[smiths]

Hi, the primary pattern of this bird fits brachyrhynchus and not kamtschatschensis, since it shows a distinct grey base to the outer web of P9, only a short black wedge on the outer web of P7 (less than half the length of the feather), and a nice symmetrical black pattern on P5-6. Most Kamchatka Gulls show more extensive black on P9 (reaching the primary coverts) and tend to show an asymmetrical black pattern on P6 or P5 (i.e. more black on outer web than on inner).
Together with the smudgy brown pattern on the neck and ear coverts (creating an 'ear patch'), as well as taking into account the location of the photographs, the primary pattern makes it safe to assume that the photos show a Short-billed Gull.

 

[Deb Burhinus]

An interesting paper! 🙂

https://www.researchgate.net/profile/Peter-Alfrey/publication/321586455_Short-billed_Gull_on_Terceira_Azores_in_February-march_2003_and_identification_of_the_%27Mew_Gull_complex%27/links/5a27d9070f7e9b71dd0cc67b/Short-billed-Gull-on-Terceira-Azores-in-February-march-2003-and-identification-of-the-Mew-Gull-complex.pdf?origin=publication_detail