Lerwick Herring Gull (Hugh Harrop)

[JanJ]

Hugh's Herring have some primary features very similar to smitsonianus, such as the pattern of p5 and 'good 'bayonets' on p6 & p7 along with the other primary characters, which might be good for smithsonianus I think.

http://www.nature-shetland.co.uk/naturelatest/pics07/Hook-Herring-Gull.jpg

JanJ

[John Bell]

Hugh's Herring have some primary features very similar to smitsonianus, such as the pattern of p5 and 'good 'bayonets' on p6 & p7 along with the other primary characters, which might be good for smithsonianus I think.

http://www.nature-shetland.co.uk/naturelatest/pics07/Hook-Herring-Gull.jpg

JanJ

Hi JanJ et al,

I'm not going to try and comment on this, I struggle to age Audouin's Gulls, but I was under the impression that adult smithsonianus 'can't be done'. At least not in Scotland. The Azores maybe (based partly on probability) but unless it is ringed or maybe a bird that returns year after year to the same location since it was a juv/1st-W (cf an Irish record) then I thought it was best to avoid them? There was an English record from Chew that ticked many boxes but ultimately didn't make it on DNA.

Of course maybe I am missing your point and you are simply drawing attention to an educational bird?

On a slightly differnt note do you know that if you take all the gulls in the world and try to construct a phylogenetic tree of them then there are more possible trees than atoms in the universe? No wonder it is complicated!

Lerwick is a fantastic spot for gulls by the way. One of the best in Scotland.

cheers,
John

[Howard King]

Lerwick is a fantastic spot for gulls by the way. One of the best in Scotland.cheers,
John

Do they all come with a bulls-eye on them !! I find it amazing that people feel it necessary to use such a heavy watermark on their pictures in this way. A great picture, of a nice looking bird - Spoilt.

[JanJ]

John,

Not about being convinced about the smithsonianus theory put forward here, more that it has some primary features - the ones mentioned, which is more common in smithsonianus compared to argenteus/argentatus, perhaps more so in argenteus. However, given the variation in both smithsonianus and the 'other two' a positive identification is probably not advicable. However, I think Hugh's gull could make an interesting point. So, I was addressing Peter Adriaens on this gull, since he would probably make something more definitive out of it, I think.

JanJ

[adriaens]

Hi Jan,

things I see in that Lerwick gull:

- P10 with short, oblique grey tongue: typical of argenteus
- P9 with rather short tongue (about 1/2 of the length of the feather) and white mirror that cuts through on outer web; black pattern of outer web reaches primary coverts: all more in line with argenteus
- P8 with relatively short tongue (clearly shorter than on P7), with little or no white on the tongue-tip; black pattern on outer web ends rather bluntly towards the primary coverts: all typical of argenteus;
- presence of a black 'bayonet' pattern on the outer web of P7 is rare in argenteus, but it happens (in slightly over 1% of birds);
- the sharply black pointed pattern on P6 is not unique to smithsonianus, as it is seen in about 60% of adult argenteus too.
- The complete, thin, W-shaped black band on P5 is shown by a minority of adult argenteus too (about 7%).

In conclusion, I think there is nothing that excludes argenteus here.

I do believe that a small minority of adult smithsonianus can be idenitified wherever they turn up, be it in the Azores or in Scotland (or Poland for that matter...), but those will normally be birds with a typical primary pattern that recalls adult Caspian Gull in some ways. A cachinnans-like tongue on the underside of P10, for instance, is a good starting point.
The Chew Valley bird was definitely lacking in that feature, and therefore I have always felt it was not a particularly good candidate (http://www.birdforum.net/showpost.php?p=1218154&postcount=27).

Peter

[JanJ]

Alright Peter, thanks for that!

Not surprised really but the p10+9+8 pattern you mention I did consider as well, so my reacting on Hugh's gull was more the 'bayonet' pattern on p7+6 and p5 pattern. Interesting views by Keith though, as I to had doubts of the Chew Valley bird - although the variability in smithsonianus on geographical grounds has to be considered. How much do we actually know about that up to date?
Bird like this would probably stand a better chance:

http://www.pbase.com/matswallin/image/89930884

http://www.htc.net/~kdan/IMG_2958.JPG

JanJ