Tuesday, February 05, 2013

Mixenden Res'r

I found this large gull late morning at Mixenden and it conveniently landed on the buoy displacing an adult L B B Gull which was appreciably smaller. No scope!!! so dashed back for it and luckily the gull was still on the bouy when I got back. I managed to get a few digishots but it moved off, went high and drifted off >SE around 12.15.

First thing that struck me was its poise (very upright stance) and the shape of the bill leading straight to the sloping forehead, and particularly the long legs suggesting the possibility of Caspian Gull? It looks like a 1st winter bird? BUT I have not seen Caspian Gull before and would welcome comments. The other possibility is Gt B B Gull but I thought it looked too pale?



9 comments:

martynbirder said...

Interesting bird Dave, I can see why you think it may be a Caspian, especially on the first photo when it looks very alert and upright. However the photo does not show enough detail to id it correctly and the quite heavily marked breast and belly points towards Herring Gull, a quite advanced bird going into first-summer plumage or a poorly marked bird going into second-summer which the tertail pattern suggests. You really need to see the markings on the mantle feathers to id a 1st winter Caspian,a very hard subject 1st calender year Gulls especially when they are going into 1st summer, Martyn

Brian Sumner . said...

Thats a hard one Dave, some features go to Caspian and some to GBB.
The mantle looks Caspian but the head more GBB apart from the slim neck.
Suppose to be easier in flight with Caspian having long slender wings as opposed to GBBs wide blunt ones but Im only going by the book having never seen a Caspian so we,ll have to wait for the gull experts to come in on this one.
Well picked out at any rate whatever it turns out to be.

David Tattersley said...

Interesting how a bird can look so different in photos 1 and 2, bird is much more alert and upright and bill appears longer in photo 1, anyhow all dark large bill is right for Caspian but I feel you would expect it to have a cleaner whiter head than this bird has, therefore I personally do not think the head markings and shape of the head plus what appears to be a fairly large eye would suggest Caspian Gull.
In addition to that this bird has tertials with bold white tips and fringes with legs that seem to be long and pink particularly in photo 3. The wing coverts appear mostly white with fairly well spaced barring which to me would suggest that this individual is more than likely a 1st winter Great Black-backed Gull but I know from my own experience that Caspian Gull cannot reliably be identified from long-distance digiscoped shots as I photographed a bird in October 2007, then sent the photos off to Alan R Dean a renowned UK gull expert amongst other things who confirmed to me that he was as sure as he could be that it was an adult Caspian Gull, however it was subsequently decided by experienced local birders that it was more than likely a Yellow-legged Gull!

AndyC said...

im pretty sure if Id seen that gull I would have said 1st winter GBBGull but as everybody says its too difficult from digi photos and large gulls are allways problematic...the white tips to tertials suggest 1st winter Caspian and the pale undertail also. .Did you get any flight shots...Well done for getting the pics Dave it was a poor day out there today.

DJSutcliffe said...

Thanks everyone for the comments on the gull. I will certainly not be claiming Caspian but it has aroused a lot of interest which is great.

We were in Sheffield today so I called in at Neepsend for an hour+ - its the Sheffield landfill. Lots of big gulls (500+ mainly Gt BB and Herring) at the day roost next to Parkwood Road and only 50m away from them but looking through a fence was a bit restricting. There has been Caspians there recently but I couldn't find one and there were no other birders around which was a shame. Oh what a nightmare - they all look different! and the juvs/immatures etc are so variable, even those more or less the same age group. I enjoyed it immensley but came back baffled by some of them. it's good to look at them in detail, so hopefully I will be calling there again on my next trip to Sheffield. It's a learning curve, and a very interesting one!!

martynbirder said...

sounds like paradise Dave, how I miss the Gull roosts and the tips

DJSutcliffe said...

Martyn Garner has come back and regarding the possibility of Caspian can't be 100% sure bit Thinks this is a first winter great black backed. These can trick sometimes. Unfortunaty.
Many thanks for your comments Martyn.

DJSutcliffe said...

David Crawshaw has also come back with comments - " I am not sure if it is a full Caspian, but it looks to have some Caspian in there, but it could well be a Herring/Caspian hybrid, they are common in Poland. The bill does not quite look 100% and it does not seem pot-bellied enough, but both of these are difficult to judge. "

DJSutcliffe said...

Many thanks to all who have contributed to the debate. We will never know now of the true identity of the Mixenden bird but it has created a lot of interest in big gulls. What a fascinating group they are and I for one will be hoping to widen my knowledge and appreciation of them. Many thanks everyone.