First winter Herring gull with venetian blind pattern (2 Viewers)

[martyrynin]

Hey,

I saw this first winter gull in the water today.
My initial impression was Great Black-backed gull, mostly because of the contrast between white head and darker body. I know not a good way to ID, but it was enough to make me curious, so I snapped some pics to look at later.

Having seen the little triangles on the greater coverts and the white notches on the terials, I'm confident that this bird is a Herring gull.

I did however out of interest fire the images into Picture Bird. As usual the ouputs were all over the place, but one thing did interest me.
The in-flight images were coming up as Caspian. I don't agree, but to be fair to the app I think the reason it's confused is because this bird appears to have the venetian blind pattern.

Firstly do you agree that the bird has this pattern? And is this pattern common in first winter Herring gull?

Thanks for reading!

 

[gozdarski.pticogled]

I don't see any cachinnans traits. Head is nicely streaked, coverts have a distinct checkered pattern, tertials have white notching and tail pattern seems spot on for HG. Pretty much textbook 1st-winter argentatus for me.

 

[martyrynin]

I don't see any cachinnans traits. Head is nicely streaked, coverts have a distinct checkered pattern, tertials have white notching and tail pattern seems spot on for HG. Pretty much textbook 1st-winter argentatus for me.

I agree completely that it's a Herring gull. I'm just more curious about the terminology.
Does this gull have a "venetian blind pattern" ?

Here's another similar gull: Gull Research Organisation

 

[gozdarski.pticogled]

Yes. Venetian blind is quite common in fact I don't remember seeing many or any (for that matter) 1st winter HGs without it.

Does this gull have a "venetian blind pattern" ?

 

[martyrynin]

Yes. Venetian blind is quite common in fact I don't remember seeing many or any (for that matter) 1st winter HGs without it.

Cool! Wasn't sure if venetian blind was a caspian gull specific thing.

I'm especially thinking about p9 and p10 though, which look dark and missing the pale "inner web" (I think that's right) in a lot of photos of first winter herring gull that I can find.

E.g.

Gull Research Organisation

This website deals with the taxa argentatus & argenteus. Comparison of plumage month by month.

gull-research.org

 

[martyrynin]

Here's the zoomed in wings of a Caspian gull, and this herring gull, both first winter.

Interestingly in this zoomed up view Picture Bird actually IDs the wing as Herring, which is quite cool; might be able to pick up on the greater covert triangles when closer up.

Anyway, both have white on the inner webs of all primaries, just about.
Looking on gull research, this isn't the case for all Herring or Caspian first winter gulls. I wonder why that is, and if it matters at all in regards to ID. Maybe its bleaching?