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Intermedius or fuscus?
Posted: Wed Sep 21, 2011 11:42 am
by Jelle VdB
Hi
These pictures were taken in Stockholm on september 8 of this year.
Any of you a thought on the subspecies of this LBBG? Intermedius or fuscus?
Re: Intermedius or fuscus?
Posted: Fri Oct 07, 2011 6:53 am
by marsmuusse
Hi Jelle,
Difficult to say. Early September is about the point where intermedius should be moulting inner primaries. On location and P1 halfway I would say "pale end of fuscus".
We have several such birds, photographed one month earlier in Stockholm:
http://www.israel.gull-research.org/05cyaug.htm (last example is not clear: fuscus / intermedius).
One of the essential issues is late primary moult in fuscus. Replacing P1 or P1-P2 should be the limit for fuscus prior to migration; where intermedius of course continues the complete moult into autumn and early winter.
Primary moult scores on ringed intermedius in September and pms on mixed flocks in the Netherlands are presented in 5 tables on this page:
http://www.gull-research.org/lbbgaugsep/05cysep.htm
Cheers, Mars