Sunday, August 29, 2010

Gull ID !

These are the gull photos from David Crawshaw all taken within a half-hour period in April this year at Orfordness, Suffolk. See what you think!










14 comments:

Jim Welford said...

I'll kick off with;

1. Iceland gull
2. Caspian
3. YLG
4. Still thinking

Jim Welford said...

Ring billed

Steve Blacksmith said...

i'd go for
glaucous, ist winter
iceland " "
iceland " "
iceland adult, non-breeding
now i'll look what the experts think.

Andrew Huyton said...

I'd go for Glaucous Gull, the next 2 I think are the same bird and I'm going with Herring Gull and the last one I'll say is Caspian. Lots of very different ideas, I've not consulted any books before I took these guesses.

AndyC said...

glauc
herring
YLegged
Caspian

heavy birder said...

Dont think any off them are Iceland or Glaucous Gulls

martynbirder said...

I was once told by a leading id expert that there is nothing worse than trying to id a gull from a single photo!

1. I think this is either a worn first summer Herring Gull with an advanced bill pattern or is it leucistic? Can't see this being a Glaucous not with dark primaries, a darkish secondary bar and dark patches on the wing coverts and tail. Could be second summer Herring it's hard to make out any grey on the photo.

2. 1st summer Herring

3. 1st summer Yellow Legged Gull

4. 1st summer Caspian

David Pennington said...

1. looks like it could be a hybrid - maybe Glauc x Herring. Haven't looked at the other ones properly.

martynbirder said...

I don't think photo 1 is a hybrid, they are very rare in the UK most suspected being Leucistic Herring Gulls

They are small numbers in the Glaucous Gull colonies in western Iceland (where HG is scarce)and they nearly always look like Glaucous but with darker primaries, wing coverts and tailbands

Alastair said...

I'm with Martyn on these gulls, he's spot on. The top pic is the hard one. I'd favour herring Gull but it's a rubbish pic that fails to show enough to nail the id but there's enough there to rule out Iceland or Glaucous and hybrids are very rare and why should it be one when it looks pretty much just like a Herring Gull? No doubt it will come out as Caspian for some reason or other (although on this view the head and eye are wrong) but on a view like that you'd never nail it in the field so I'd stick with Herring Gull.

The tertials are one of the big clues to the id of the other three and they look text book to me.

David Pennington said...

I agree the hybrid option is often a bit of a cop-out and this isn't a very good pic so yes, maybe leucistic HG. Surely not a typical HG though, unless it's over-exposed or something? Dunno, still looks to have a bit of Glauc in there to me, structurally as well as plumage-wise.

David Sutcliffe said...

Well done everyone for having a go - not easy from single photos and the debate may well continue. The tertials are the big clue on the 3 standing birds.
I have it on good authority from David Crawshaw that they are:
Glaucous/Herring Gull hybrid
Herring Gull
Yellow-legged Gull
Caspian Gull

Sorry no prizes!!!

AndyC said...

Not bad with the savis thats 4 and a half out of five..I based my Glauc on the bill only did'nt realy look enough.

martynbirder said...

First of all I'll say thanks for this very interesting post, got the old grey matter ticking over.
Can you get any better photo's of this possible hybrid Dave, from what I can see in this photo it's Luecistic Herring. In Iceland I used to watch a flock of about 100 immature Glaucous of varying ages (but mostly 1st summers) which contained six Hybrids (or probables) and I also saw a second generation adult breeding with a pure Glaucous and they always looked like Glaucous in structure and general features. I also saw a few hybrids in California but was never very sure if they were Herring x Glaucous or the more likely Herring x Glaucous Winged, the paler birds looking exactly the same. In summary the identification of a hybrid away from a known area of hybridization such as eastern Iceland is unsafe.
Must admit that it does look to have the typical 1st winter Glaucous bill tip pattern.

Anyone with an intrest in this difficult (almost impossible subject!) should check out GULLS by Klaus Mailing Olsen and GULLS OF THE AMERICAS by Steve Howell, lots of known and presumed hybrid photo's in there, ADVANCED BIRDING by Kaufmann is also very good