Which gull is this one?

[RoyW]

Originally Posted by loripo

They do look so similar to me. What would have made it possible to decide?
(usually where I am by the THames we see black-headed or greater black backed).

Most similar immature gulls are best identified by looking at the pattern of markings on the wings (with either a side view or in flight), in particular the patterns on the tertials and greater coverts (as mentioned by Dogghound).
Wing length, bill size/shape, and the overall structure of the bird can also be useful with experience.
There are some differences in the patterns usually seen on the head and breast, but because immature gulls can be extremely variable these characters cannot be safely used for ID without being backed up by other features.
The colour of the "adult type" upperpart feathers is obviously also of use in older individuals.


Are you sure that the gulls that you "usually see" are all Great Black-backed? I would think that it likely that you see some GB-b Gulls, but Lesser Black-backd and Herring Gulls typically greatly outnumber GB-b Gulls in the London area (including along the Thames).

[loripo]

No - having looked thru my photos I find they aren't what I thought. I'm OK (I hope) with Black Headed


But this that I thought was GBB has yellow legs (?)

So how about these last two!

[Dogghound]

Your GBB is a LBB.

I can only see one photo and a red cross at the bottom, the photo shows a (3rd year) herring gull.

[solus]

No. 3 is a Lesser Black-back - they're the ones with yellow legs while GBBs are bigger, darker and have pink legs.

No. 4 is a Herring Gull with mud covering the lower part of its pink legs and feet!

The first two pics are Black-headed Gulls and the last one is just a little red "x" in a box on the post?

The immatures of the larger gulls are a nightmare and I'm afraid I tend to pay them far less attention than I should.

[david156]

Hi lori.

With referance to your gull id problems, heres a picture of a Herring Gull and a Great Black Backed Gull that i took, giving you an idea about size



cheers David

[Dogghound]

This gull is a herring gull (I think).

[RoyW]

I agree with all the ID's already given for the newer post.

Including this one:

Originally Posted by Dogghound

This gull is a herring gull (I think).

The tertials are relatively plain for a 1st year Herring Gull, and overall the bird is quite dark, but it does look like a Herring Gull (the image can be viewed if you click on the red 'X', it's just the thumbnail that isn't showing properly).

[Dogghound]

Originally Posted by RoyW

The tertials are relatively plain for a 1st year Herring Gull, and overall the bird is quite dark, but it does look like a Herring Gull (the image can be viewed if you click on the red 'X', it's just the thumbnail that isn't showing properly).

The greater coverts look good too. Had to look twice at the tertials though, not a lot of notching but it is more prominent than you would expect in a LBB. Interestingly although unlikely in this case, plain tertials can be suggestive of northern European birds.

[RoyW]

Originally Posted by Dogghound

The greater coverts look good too. Had to look twice at the tertials though, not a lot of notching but it is more prominent than you would expect in a LBB.

The greater coverts are exactly what I would expect on a Herring Gull (not so prominently barred on LB-b). I said that it looked like a Herring Gull, but forgot to say why!

Originally Posted by Dogghound

Interestingly although unlikely in this case, plain tertials can be suggestive of northern European birds.

There's no real reason why it couldn't be a northern European bird. The exif data shows that the photo was taken in mid October, which isn't too early for the first wintering birds to arrive from further north, and argentatus race Herring Gulls are easy to find around London during the winter (although they aren't always easy to identify as this race! ).

[loripo]

Thanks for the response. Also useful to see the size comparison as what I thought was large isn't the largest after all!
The photo with no thumbnail was taken in Hyde Park, by the Serpentine. The others were all nearby where I live on the South bank of the Thames.
I'll go thru the replies later to get it all straight