Gull Moult

[Josh Jones]

Both birds seen today (10/2), both perhaps unusual in moult?

The first three images are of a 2CY bird, which appears to have retained much of its juvenile feathering.

The last image is of an apparent 3CY (2w) bird, but the bill seems very advanced (more of what I would expect in an older bird)...

Comments welcome...

[JanJ]

Hello Josh.

The explanation to why (if we assume it´s a healthy individual, and not hatched extremely late) your first Herring Gull has retained it´s juvenile plumage into Feb. in it´s 2cy you´ll find here by looking at the argentatus HG,s here:

http://www.gull-research.org/hg/HG2CY01.htm

The second gull is more difficult to identify as to species (although Herring comes to mind) and age, but by the look of it´s - at least second generation coverts, presumably older than 2cy but the yellowish bill seems well ahead of it´s age type, and made me think of these 2cy Baltic Gulls, which usually mature faster compared to a Herring Gull.

http://www.elisanet.fi/hj.koskinen/2cyfusC10H.html

http://www.elisanet.fi/hj.koskinen/2cyfus2ndgen20070610.html

JanJ

[Josh Jones]

Hi Jan

Thanks for your response - the links are very useful.

I have just realised I forgot to state in my original post that both birds were indeed Herring Gulls!

Although clearly a Herring Gull in the field, the second bird fascinated me. The early maturation of the bill colour also reminded me of fuscus, so I thought I'd grab a few images for reference (not that I ever thought it was anything other than Herring). Typically, the bird flew off after that one shot, and I didn't see it again. Interesting bird though!

Josh

[mike meidlinger]

Hi Josh,

I agree with Jan,

Your first three pictures are of a bird in it's first winter, though showing nearly imaculate juvenile plumage...taken in mind that argentatus moults later than argenteus (fa ar more relaible feature to go on than structure/size due the variability that makes large larids famous) than argenteus...in fact...in Belfast most 1st year argentatus are found using mainly this feature from December onwards where birds are in complete juvenile attire...

There for your first photos probably relate to this race while your forth is, to me anyway, a bog-standard 2nd winter argenteus

[Josh Jones]

There for your first photos probably relate to this race while your forth is, to me anyway, a bog-standard 2nd winter argenteus

Not sure if you have misunderstood me, I was not trying to claim the birds were anything other than Herring Gulls (they both clearly are), and the ID is not being debated. I just wondered about the moult and bare part colouration, that's all. Especially the 3CY bird which, although moult is pretty average, has a quite advanced bill.