www.gull-research.org

I'd appreciate any comments on this individual, photographed in southern England on 2nd April, particularly ageing (especially generation/moult of the primaries). Regrettably, I failed to get any flight shots of this individual. Thanks,

A 2cy LBBG that has replaced all scapulars and the occasional covert. The primaries look pretty rounded for juvenile feathers!

Ruud Altenburg wrote:A 2cy LBBG that has replaced all scapulars and the occasional covert. The primaries look pretty rounded for juvenile feathers!

Thank you Ruud.

If they are (a complete set) of new (2nd gen) primaries, does this have any implication with regards to sub-species? Is fuscus more likely to show this than intermedius/graellsii?

I read that 60-80% of 2nd calendar year fuscus replace their juvenile primaries by about this date, but can't find an equivalent figure for intermedius/graellsii - though my understanding is that this would be a rare(r) occurence in more western/southern populations of LBBG.

Second generation primaries never been recorded in ringed graellsii/intermedius in spring. Very occasionally you will find a graellsii/intermedius-like bird that has replaced a few inner primaries. We have just finished a paper for Dutch Birding about 2cy LBBGs, don't know when it will be published though.

http://www.xs4all.nl/~daarruud/fuscus2ad.html
http://www.xs4all.nl/~daarruud/fuscus2af.html
http://www.xs4all.nl/~daarruud/fuscus2e.html

Interesting shape of primaries, but since the tertials and most wing coverts are still juvenile, the primaries should all be juvenile too, I suppose.

Thanks for both the further comments.

I'll look at the paper you mentioned, Ruud, with interest.

Do we see a 2cy graellsii/intermedius with a complete set of new second generation primaries? I should think not.
It´s anyway interesting with obviously rounded primary tips in a gull with first generation primaries one here). Check out the primaries on the second January LBBG here (http://gull-research.org/lbbg1cyb/ajahred.html) . Could it be angle (in some of the cases), type of wear etc...

JanJ

JanJ wrote:Do we see a 2cy graellsii/intermedius with a complete set of new second generation primaries? I should think not.
It´s anyway interesting with obviously rounded primary tips in a gull with first generation primaries one here). Check out the primaries on the second January LBBG here (http://gull-research.org/lbbg1cyb/ajahred.html) . Could it be angle (in some of the cases), type of wear etc...

JanJ

Thanks Jan. I guess the conclusion is that they are simply very fresh, black and round-looking first generation primaries. Which makes everything else fall back into place. How we could do with some definitive, ringed (fuscus) individuals to get to grips with over this side of channel!