3 gull ID questions (4 Viewers)

[JayFeatherPL]

Hello!
Got three questions regarding gull identification. Hope you can help me!
1.How can I separate "atlantic" Yellow-Legged Gull (Larus michahellis atlantis) from "british" Lesser Black-backed Gull (Larus fuscus graellsii)? Both these gulls have a very similar dark mantle shade. Or even L. m. michahellis from Lesser Black-backed Gulls with paler mantles?

2.How can I separate Yellow-Legged Gull from Herring Gull "omissus" type, i.e. with yellow legs and an intensive red orbital ring?

3.Is it possible to separate Iceland Gull ssp. Thayeri from the other large gulls, especially from Herring Gull? In the Collins Guide, it is written "in the light of the current knowledge it is hard to identify them unambiguously".

Thanks for the answers in advance!
Have a nice day or night!

 

[leifvester]

Hi Jay,

Here's my fairly novice two cents.

1. Yellow-legged gull is a larger, more powerful gull than a lesser-black backed gull, which is slightly smaller than a herring.
The LBBG will have a more slender profile, and appear less bulky.
The bill on the YLG will likely appear more bulbous, whereas LBB will be more compact (not have an extreme gonys angle)
The leg and bill colour on YLG may appear more pastel yellow, perhaps with a green tinge, whereas an adult LBBG will have orange/yellow bill and legs.
YLG will be longer legged.

While Azores gull may have a darker mantle than nominate YLG, I was lucky enough to see one in Mayo this year, and it very much looked closer in shade to Common Gull than LBBG, which even in graellsii can still look like a fairly dark slate.
Kodak scale shows that there definitely can be overlap, so probably not reliable to use mantle colour!
(8-10 Graellsii)
(7-9 Azores)
(5-7 Common, Argentatus)

Key takeaway here imo, is compare against Herring gull, as it won't structurally look much like an LBBG.

Fwiw when we went to see the Azores gull, we all thought it was a Herring gull upon initial glance, until we got bins on it.
A caveat here is that I have seen a lot of lesser black-backed gulls, but very few yellow-legged gulls, so this may bias my ID approach.

2. The book Gulls of Europe, Asia and North America actually answers this exact question in five detailed points, that cover structure, primaries and winter head pattern. It's a bit too much to type out, and too specific to summarize any more than already done in the book.

3. Iceland gull is on my wishlist to see

 

[Earnest lad]

With the all the Yellow-legged Gulls I have seen (Canary Islands, UK, and central Europe) , the yellow was distinct bright yellow in hue. All the ones I saw were adult birds. I have had a look at google images pics of the omissus Herring Gull. It seems to me the yellow of that one's legs usually tend to be of a somewhat more subdued tone of yellow. However I am not an expert and stand to be corrected if I am wrong. I hope this helps a little.
Also, I have read that in general, the upperparts of the Yellow-legged Gull tend to be darker than Herring Gull but paler than found in Lesser-black backed Gull.

 

[JayFeatherPL]

Hi Jay,

Here's my fairly novice two cents.

1. Yellow-legged gull is a larger, more powerful gull than a lesser-black backed gull, which is slightly smaller than a herring.
The LBBG will have a more slender profile, and appear less bulky.
The bill on the YLG will likely appear more bulbous, whereas LBB will be more compact (not have an extreme gonys angle)
The leg and bill colour on YLG may appear more pastel yellow, perhaps with a green tinge, whereas an adult LBBG will have orange/yellow bill and legs.
YLG will be longer legged.

While Azores gull may have a darker mantle than nominate YLG, I was lucky enough to see one in Mayo this year, and it very much looked closer in shade to Common Gull than LBBG, which even in graellsii can still look like a fairly dark slate.
Kodak scale shows that there definitely can be overlap, so probably not reliable to use mantle colour!
(8-10 Graellsii)
(7-9 Azores)
(5-7 Common, Argentatus)

Key takeaway here imo, is compare against Herring gull, as it won't structurally look much like an LBBG.

Fwiw when we went to see the Azores gull, we all thought it was a Herring gull upon initial glance, until we got bins on it.
A caveat here is that I have seen a lot of lesser black-backed gulls, but very few yellow-legged gulls, so this may bias my ID approach.

2. The book Gulls of Europe, Asia and North America actually answers this exact question in five detailed points, that cover structure, primaries and winter head pattern. It's a bit too much to type out, and too specific to summarize any more than already done in the book.

3. Iceland gull is on my wishlist to see

With the all the Yellow-legged Gulls I have seen (Canary Islands, UK, and central Europe) , the yellow was distinct bright yellow in hue. All the ones I saw were adult birds. I have had a look at google images pics of the omissus Herring Gull. It seems to me the yellow of that one's legs usually tend to be of a somewhat more subdued tone of yellow. However I am not an expert and stand to be corrected if I am wrong. I hope this helps a little.
Also, I have read that in general, the upperparts of the Yellow-legged Gull tend to be darker than Herring Gull but paler than found in Lesser-black backed Gull.

Thank you for the answers!