Lack of black showing in primaries is apparently usual in a 1st summer Arctic Tern and at this time of the year could also be due to bleaching by the sun!
I photographed (not very expertly!) a juvenile Arctic Tern at Scout Dike on 01/10/07 and for plumage comparison thought it would be a good idea to include it on here, hence the new thread.
The bill shape is identical as is the the head shape of the bird and the short legs make the bird look dumpier in appearance than a Common Tern or a Roseate Tern would do. Bearing in mind that this bird was photographed on 1st October (ie 18 days later than yesterday's bird), although I appreciate that the appearance of Terns can change rapidly at this time of the year, I still think the possibility of juvenile Arctic Tern moulting into 1st winter plumage is not likely.
It was mentioned that the mystery bird called at times, what did it sound like? I should have thought It would have sounded noticeably different to the Common Tern present if it was a Roseate Tern.
I could be completely wrong but I am 99.9% certain in my own mind that yesterday's mystery bird is a 1st summer Arctic Tern which is still a great record and one that is rarely photographed having trawled the internet for the last hour or so.
Well Done Dave, Nick and whoever else was present at the time!
14 comments:
I've not really been following this too closely but don't the majority of first summer arctic terns stay down in Antarctica? Only a few return I believe and as such this plumage is rarely seen, well done to all involved in this interesting exercise. From what i recall many years ago wasn't this plumage form called "portlandica" after a bird in this plumage first seen at Portland?
I'd agree with this being a first summer Arctic Tern, this is illustrated well in Terns of Europe and North America which also includes a photo, must say I've only ever seen two before, well done David great find
I would have thought the bird in question is in first winter plumage. Surely by its second September it wouldnt be still showing juvenile features to its tertials and mantle. An old copy of Birdwatch april 1995 has a good article on Artic and Common terns it also says Portlandica relates to Common Tern ??? I can not find the May 1995 Birdwatch which has an artticle on Roseate Terns if anybody has it I would Like a look please.
I think there has been a little mix-up here, the bird I am refering to is the Ogden Arctic, not the bird photographed here, although I must say I think this is actually a 1st winter Common Tern not Arctic, surely Arctic Tern does not aquire any red on the bill until it's second summer? Anyway going back to the Ogden bird I think it is 1st summer Arctic moulting to 2nd winter.
No I was refering to the Ogden bird. I think its in its first winter plumage. The Arctic Tern picture you have posted shows no markings on the tertials or mantle where as the ogden bird does.
a good point but it is fasr to early for 1st winter plumage, juveniles do not moult until late October, usually in winter quaters, there is also a trace of a dark covert bar appearing, but that said there is very little differece between 1st winter and 1st summer
Just to put the record straight the comparison photo I put on the blog is most definitely a juvenile/1st winter Arctic Tern Tern Martyn.
It was seen very well at rest and in flight at Scout Dike & probably earlier at Royd Moor over a period of at least 4 days and was seen & photographed by a number of very experienced birders during that period of time who had no doubt it was an Arctic Tern.
It seems clear that a consensus of opinion is unlikely to be reached on the Ogden bird, but having looked at a number of photos I personally took of family groups of Arctic Tern in NE Scotland at the end of August 2007 I have come to the conclusion that plumage including bill colour in particular seems to vary enormously in juvenile/1st winter/1st summer Arctic Tern.
Yes, just to reiterate what David T said - the 2007 Scout Dike tern was 100% an Arctic.
Re. the Ogden bird - what about biting the bullet and putting it on Birdforum/Surfbirds? You don't have to agree with any responses.
I'm not disputing that it was not an Arctic, I just think it looks like a Common, every bit of info I have states that Arctic never shows red on the bill in juvenile plumage, pretty intersting though
more research needed
Ah, I see the Ogden tern is already on Birdforum.
Ogden mystery tern. Interesting one. Age first - looks like a bird in 1cy to me. 2cy birds do not show the brown - blackish - pure white to the ends of the tertials that this bird shows - ref Olsen and Larsson but also personal obs this summer (this age occurs here and in Shetland quite commonly in late summer), watching a number of 2cy birds on Orkney in July. I can also see brown edges to some of the scapulars that would be consistent with 1cy and not so with 2cy. The primaries are dark with darker tips and a white edge, consistent with 1cy plumage rather than the more uniform and less contrasting primaries of a 2cy bird. Bare part colours are consistent for both ages, Arctic loses the redish bill colour shortly after leaving the nest area. Thus my view would be that this tern came out of the egg this year.
With the age sorted the ID is relatively straightforward. Very short legs, a very fine delicate bill are good for Arctic Tern, not so good for Roseate. The head pattern is typical Arctic Tern of this age with a pure white forehead and lores and a dark eye mask without an eye ring, very unlike a Roseate of this age.
I can't find any reasons not to identify this bird as an Arctic Tern in it's first calendar year.
The other contested ID, of the tern at Scout Dike is also pretty clear cut. Obviously in its 1cy the bird has fledged late and retained the orange / red in the bill. It has very short legs and a very fine bill, the head pattern is typical Arctic Tern. (Sorry to disagree with you Martyn.) This is an Arctic Tern in 1cy also.
Over recent years (in Yorkshire as well as Orkney) I have spent an aweful lot of time looking at terns, I don't think they are an easy ID and take a bit of "tuning in" to. I'd recommend taking a similar approach to gull id, practice ageing them in the field when you get the opportunity and look at loads of photos - still waiting to find my first rare though.
Thanks AL I totally agree with you on the age of the Ogden bird. There does seem to be some confusion on the term Portlandica though, I was informed that this related to arctic tern but an artical in Birdwatch april 1995 mentions it under common tern ? is this a mistake, the article was by Olsen and larssen.
no problem Alistair, I've been having a good read overnight and also came to the conclusion that the Scout Dyke bird must have been a late fledging juv, an odd plumage for the time of year though, I must also admit I don't get to see many Terns especially in juv and immature plumages, I'm off down south in two weeks so I should see plenty of 1st/2nd years, can't understand why all the text books state that Terns migrate in juv plumage moulting in to 1st winter in wintering grounds, does this tie in with what you see in Orkney?
p.s. you might have realised I don't know as much about Terns as I though!
Thanks alistair,do all these first year birds on Orkney allways show black legs or are some dark orange .?
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