Ageing large gulls (1 Viewer)

[TimJC]

I've been trying to get to grips with the large gulls recently and specifically ageing them. Now, I thought I had got to grips with juv. > 1st winter > 1st summer > 2nd W. etc., but then I come here to test myself on some photographs and everyone is using 1st, 2nd, 3rd CY! :eek!:

Could someone please explain how the two systems translate, I'm sure it's simple but when I think I've worked it out I get it wrong. Is 1st CY simply juv. and 1st W. encompassed into one category, and therefore 2nd CY will be 1st S. and 2nd W., and so on?

 

[Clive A]

I think that's about right Tim.

 

[mäkpe]

I think that's about right Tim.

No it's not. 1cy is a bird in it's first calendar year so from the birth to 31st December, then in 1st of January it turns to it's second calender year = 2cy and so on. 1cy is juvenile at least in Northern hemisphere, but 1st winter could be as well 1cy as 2cy etc.

 

[Andy Hurley]

When someone uses cy, as explained by Mäkpe, it could be that they are having difficulty with the phase of plumage possibly due to moult state. So if its half way between summer and winter plumage it may well have features of both, so saying 2cy, for example would cover all eventualities. More acurate would be 2cy moulting to 2nd winter with some features of 2nd summer retained, but thats quite long winded.

EDIT: After Lou's post(see below) the last sentence should read 2nd Winter with some features of 1st Summer retained. Which makes sense really, because during the first calendar year, it is in juvenile plumage and not 1st Summer plumage, but it causes (me) some confusion.

 

[lou salomon]

it get's even worse if you use the moult cycle system, used in america and recently spreading among some larophiles in europe as well, tim. all systems are based on different criteria:

1. juv - 1st winter - 1st summer etc. is the conservative system more or less describing different plumages. problems: 1st summer, 2nd summer etc. commonly being confused with the summer it was hatched (= juvenile), respective 2nd summer being the 2nd summer after hatching - which is wrong. second problem: the "summer plumages" (in america called "alternate plumages") are not scientifically accurate in terms of being separate plumages but merely a transition form attained by wear and ongoing moult to the more clear "winter plumages" (in america called "basic plumages").

2. calendar years: this is the widely adopted system in europe to accurately name a birds age, described by mäkpe above: 1cy includes juvenile and 1st winter plumage and lasts from hatching to 31st december of that year, 2cy comprises even three "plumage types" of the conservative form: 1st winter, 1st summer and 2nd winter, etc...; so this system merely says how old a bird definitely is without describing its plumage. if you know the date of an observation/photo in combination with the calendar year you can deduce the 'plumage type' of a gull.

3. moult cycles. used on the other side of the pond, this system is based on the moult: 1st cycle starts with hatching and ends when the first primary gets replaced (usually in late spring, early summer) - and when second cycle is starting. the timing of moult cycle change slightly differs from species to species with the more northern breeders usually starting a bit later with the 2nd cycle, also, as you might know, younger birds start to moult their primaries earlier than older ones which sets the cycle change a bit earlier. the naming of a gull's age in this system is: juvenile -> 1st basic (i.e. 1st winter) -> 1st alternate (1st summer until primary moult starts), 2nd basic -> 2nd alternate etc.
hope i didn't mess this up and i hope it helps. in england most people seem to cling to the old system of juv - 1st winter - 1st summer etc. which is good enough to be comprehensive for most birders, so go ahead and go for good gulling! :t:

cheers

 

[Steve Arlow]

As Andy has pointed out using the Calender Year approach is perhaps not ideal on its own and you may have to say early 2nd CY or late 2nd CY etc, or as the example he has provided.

As 1st CY bird in January will look different to a 1st CY bird in December. In January its plumage will be mostly 1st winter (with moulted Scapulars etc) and in December will be mostly 2nd winter plumage.

Personally I don't like the CY approach as it fixes the bird to our calendar with to great a variation within that 12month period and not to the stage of its actual moult, is 1st winter, 2nd winter, adult and so on.

 

[lou salomon]

As 1st CY bird in January will look different to a 1st CY bird in December. In January its plumage will be mostly 1st winter (with moulted Scapulars etc) and in December will be mostly 2nd winter plumage.

you meant 2cy january - 2cy december, steve, didn't you? 8-P

 

[TimJC]

Thank you for taking the time to reply everyone, especially with so much detail Lou.

I think Steve's post highlights perfectly the problem you mention with the juv. > 1st winter > 1st summer system :-O.

I won't pretend I fully understand the American moult system eek! but calendar years now make sense at least!

 

[Steve Arlow]

Yes I did mean 2nd CY but I guess the example still work|:$|

 

[tittletattler]

Ah! A perfect opportunity for a bit of gull related trolling. :t:

Please see attached. Both images were taken on 16th Feb 2007. Each pic shows a YLG (with a cheeky Casp in the foreground in the 2nd image). One YLG is more advanced than the other. Both are 3rd calendar year.

One YLG is in 2nd winter plumage. So, is the more advanced bird 2nd summer then? Even though it's 16th Feb?

Some YLGs can show summer plumage...well....now! Certainly in December at any rate. So, would you report them as 2nd summers in December?

For me, this is why 'calendar year' works so much better.

Cheers,

Andy.