Larus canus v Larus Heinei? Epping Forest (NE.London) (1 Viewer)

[KenM]

Found this Common Gull amongst a flock of circa 40 BHGulls yesterday on forest land (Epping Forest).

I took a few “flight” shots and on returning home I referenced a “research gate PDF” by P.Adriaens & Chris Gibbons on the Larus canus complex.

Principally, because I was alerted to the possibility of Larus heinei which had been claimed the previous day in Richmond Park albeit being a distinctly remote chance, I knew that I had to swot up on “the differences” between the two taxa.

I’ll cut to the quick, it was stated that only 1% of L.canus birds had a “broken” bridge on P4 compared to L.heinei within which this feature is a constant?
Further, a small white mirror on P9 and a solid black tongue on P4 should also be requisite feature for “heinei?”

At the very least I’m hoping for a “one percenter” as the subject bird appears to conform?

Cheers

 

[Alexander Stöhr]

Hello Ken,
thank you for sharing this interesting bird.
First: please note, that your Gull has a broken band on p5 and p4 seems unmarked. Therefore, it isnt a heinei, that can be identified with confidence in Europe, as you have allready said.
More, it has an unusual wingpattern for a "normal" Common Gull, but I struggle to find the reason. Is it only the monster white mirror on p10, covering more than the half of the feather? I have the feeling, that I not see the forest for the trees. Because, with a white mirror on p8 and the general jizz this has to be a Common Gull.

Conclusion? Others, please help!

Edit: is it possible to see pictures of the claimed heinei? I am very interested in this topic.

 

[KenM]

Hello Ken,
thank you for sharing this interesting bird.
First: please note, that your Gull has a broken band on p5 and p4 seems unmarked. Therefore, it isnt a heinei, that can be identified with confidence in Europe, as you have allready said.
More, it has an unusual wingpattern for a "normal" Common Gull, but I struggle to find the reason. Is it only the monster white mirror on p10, covering more than the half of the feather? I have the feeling, that I not see the forest for the trees. Because, with a white mirror on p8 and the general jizz this has to be a Common Gull.

Conclusion? Others, please help!

Edit: is it possible to see pictures of the claimed heinei? I am very interested in this topic.

Alex hi,

we seem to have a difference of opinion on P4, If you look at the enlarged shot counting back from P10 the “last broken” black tip is on P4 if I’ve sequenced it correctly?

PS I don’t know if the “other” London bird was imaged?

Further, according to the article it would appear that there is much overlap on various features. thus I cut, to what would appear to be the salient points if I’ve interpreted them correctly?
Being the broken black tip always 99% solid in canus and the solid black tongue on P8 again favouring heinei?

Further still, a study of Larus canus in Kiel during the Winter of 2000-1….circa 50% of birds monitored were considered heinei according to a study by Olaffson et al.

Cheers

 

[pdwinter]

Alex hi,

we seem to have a difference of opinion on P4, If you look at the enlarged shot counting back from P10 the “last broken” black tip is on P4 if I’ve sequenced it correctly?

Ken - this is how I see the bird's wing (but I may be wrong)

 

[Alexander Stöhr]

Hello Ken,
like you, I hope for Lou, Smiths and others to jump in. If I remember correctly, (nearly all?) studies about wintering Common Gulls in the baltic region have relied mainly/mostly on biometrics when assigning Common Gulls to a ssp. Therefore, the largest ssp canus (from the east of the breeding range ?) were merged with heinei in these studies.
This is only true, if I interpret the DB-article by Peter Adriaens and Chris Gibbins correctly, therefore I hope Smiths jumps in.
And see here: Size doesn't matter

Here is a Common Gull with a broad band on p5 and a broken band on p4 (23. 11.2019, Brandenburg/Havel, NE-Germany)

Edit: you know, what would be "ein Träumchen" for me? Yes, ....

 

[KenM]

Ken - this is how I see the bird's wing (but I may be wrong) View attachment 1419048

Paul hi,
I may have made a mistake? but my P7 is between your p8 and your p7?

Cheers

 

[lou salomon]

one of the strong points of the new gull book by Adriaens et al. is the identification of Russian Common Gull, being presented in a rather constructive way and is easier to understand than in the monography about canus complex. This bird is an extreme canus type with very little black in wingtip, large mirrors and long tongues, so no question about it - you just didn't count correctly, Ken. p5 mark is broken and weak, p8 has a largish mirror.

 

[KenM]

one of the strong points of the new gull book by Adriaens et al. is the identification of Russian Common Gull, being presented in a rather constructive way and is easier to understand than in the monography about canus complex. This bird is an extreme canus type with very little black in wingtip, large mirrors and long tongues, so no question about it - you just didn't count correctly, Ken. p5 mark is broken and weak, p8 has a largish mirror.

Cheers Lou, I returned to site yesterday with no birds present, however today there were 5 birds with what looked very much like the “subject” bird and with better lighting I got better shots. Where one can easily “count the primaries!”

Quite right to all that counted correctly….slapped wrists for me!
I relied too heavily on what I read as a “set in stone” feature with the “broken” black tip on P4/5.
I believe, I now know what to look for regarding these two sps.👍