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Larus gull from Wassenaarse Slag, Netherlands (1 Viewer)

MaxesTaxes

Member
Netherlands
Hey guys,
I photographed this gull in January (2021) at the beach of the Wassenaarse Slag in the Netherlands. I believe it is a juvenile Larus gull, however I am having a hard time figuring out which species it belongs to. My current best guess is Larus argentatus, but if you tell me it's a L. canus or L. marinus I'll gladly take your word for it. How exactly can you best distinguish the different juvenile gulls from each other?
Thanks in advance!
Max
 

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MaxesTaxes

Member
Netherlands
I will add this one as well. Not the same individual, but maybe (not) the same species? The beak looks different but that may just be due to the lighting.
 

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Alexander Stöhr

Well-known member
Hello,
welcome to birdforum!
Large gulls are extremly difficult to identify, but here are some experts that are willing to help.
But i hope, they are needed here only for confirmation (whishing, that I can ID them correct):

First is a 3cy or 4 cy Herring Gull. Common Gull has a more slender bill and a smaller, gently rounded head. And it lacks variagated pattern on tertials and greater coverts, like your bird.

No more needed here, expert view is there!
 

Alexander Stöhr

Well-known member
Hello,
your first Gull was hatched in 2019, therefore:
It was 2019 in its 1. calendar-year (=1 cy)
2020 it was in its 2 cy
2021 it is in its 3cy.

In more recent publications, age is often referred to (moult-) cycles, nearer to plumage development.
 

Butty

Well-known member
I'm guessing that '3cy' means '3 years old',
Sadly, it doesn't mean that at all, nor even anything like it - which is why I wish someone would add a topic about ageing terminology to the 'sticky' topics at the head of this forum. (I also wish that people wouldn't use that potentially - very - confusing calendar-year terminology so much in this forum, or at least not in the many instances where it's unnecessary and unhelpful. But I realise I'm onto a loser with that one.)
 

Alexander Stöhr

Well-known member
Hello Butty,
do you think, the cycle-terminology used by some is better/better understandable/more useful? I will look into this topic more thoruoghly again.
 

lou salomon

the birdonist
ageing terminology is a neverending and old discussion. 'calendar year' still is much more accurate than just saying "year". then there are attempts in plumage categories as used traditionally in europe like 'first summer', which in gulls is 2cy, one year old. second winter would be 2cy-3cy. since plumages and especially moults don't correspond with our calendaric season system the most accurate ageing is indeed the cycle system: 2nd cycle starts (in spring) with the dropping and replacement of the first (innermost) primary.
 

Parker

Uncomfortably Numb.
Sadly, it doesn't mean that at all, nor even anything like it - which is why I wish someone would add a topic about ageing terminology to the 'sticky' topics at the head of this forum. (I also wish that people wouldn't use that potentially - very - confusing calendar-year terminology so much in this forum, or at least not in the many instances where it's unnecessary and unhelpful. But I realise I'm onto a loser with that one.)

I completely agree with you Butty the old way of Juvenile, 1st Win, 1st Sum then 2nd Win etc is far easier to understand & better for identification IMO.
 

Deb Burhinus

Used to be well known! 😎
Europe
I think whatever system works best is somewhat determined by moult sequence, which in turn is determined by whichever species one is applying aging criteria to.

‘Juvenile‘ means different things in terms of age for example - it doesn’t tell you how old a bird is (since some larger species can retain juvenile plumage for well into their second year of age) and with birds that don’t have more than one moult a year, describing seasonal cycles of moult is not applicable. I have always thought that with gulls, aging them by plumage type does make more sense than by calendar year as with any birds that take 3 or more years to maturity and go through 2 or 3 moults a year. But with the proviso that individual birds of species that take many years to full maturity, can often have retarded or advanced moult for their age group, aging them by their plumage ‘type’ therefore can be an unreliable aging criteria - that situation would apply to calendar year aging as well but perhaps the latter is more expansive in what plumage type to include.

Passerines that have only a partial post-juvenile moult before their complete moult the following summer, aging them by 2cy the following Spring makes more sense to me than saying they are in 1st winter plumage at that time of year, if they have only annual moults - ie you wouldn’t describe a Blackbird that has moult limits on it’s flight feathers in April as being in ‘first winter‘ or in ‘first summer’ plumage in the Spring of its 2cy, you would simply describe it as in its 2cy. With the larger raptors, aging is a bit more complicated by plumage type because of the variability within age group and duration of the moult cycle - Personally I find calendar year aging works better for large raptors as it encompasses all the potential and gradual moult change within one calendar year rather than trying to fit a complicated sequential moult cycle into a winter or summer plumage type. Of course if the objective is not to age the bird but to describe its plumage, ‘juvenile’, ‘immature’, ‘sub-adult’ etc works fine. I personally am happy to follow literature - particularly Forsman etc in describing age definitions in raptors. Unfortunately, the field guides a lot of birders rely on, use the seasonal cycle so within the field of ornithology, there’s inconsistency.

I suppose in short, aging birds can be complicated and whatever system best reflects the moult strategy in terms of timing and duration for each species/genus might be the best one.
 
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Butty

Well-known member
In April, a blackbird that is (almost) 1 year old is a 1st-year. And it stays a 1st-year (qualify that by 1st-winter, 1st-spring, 1st-summer, 1-year-old or whatever fits) until its post-breeding moult in late summer/autumn. Clear, unambiguous and (crucially) intuitive.
 
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ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

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