Which Black-back? Central NY State 2/26/22

[MWM]

Taken today in Geneva NY, looks like a Greater but with yellow legs. (One pic has regular pink-legged Great Black-back for comparison).

[Sneat]

Looks fine for a Great Black-backed Gull to me. Bill is larger than I would expect for a Lesser Black-backed Gull and back just slightly darker. There is also not a noticeable size difference between the two birds in the comparison photo, a Lesser Black-backed Gull would be significantly smaller than a Great Black-backed. The legs are tinged yellow, but I would expect more bright yellow to conclude Lesser Black-backed Gull, especially when the individual has a clean unstreaked head. 

[RobinHood]

Agree with Greater, bill size and too dark for Lesser.

[chipperatl]

How do we explain the yellow legs?

[IKLland]

3 minutes ago, chipperatl said:

How do we explain the yellow legs?

Uh oh…

[MWM]

I was checking out Great Black-backed Gulls on Ebird, some of their files pics show adult birds with pale yellowish legs? Wonder if it's a Breeding/Non-breeding trait?

[chipperatl]

On 2/27/2022 at 6:26 AM, MWM said:

I was checking out Great Black-backed Gulls on Ebird, some of their files pics show adult birds with pale yellowish legs? Wonder if it's a Breeding/Non-breeding trait?

Listening to a presentation on Gull ID by Amar Ayyash and he just mentioned, 2-3% of Great Black-backed Gulls have yellow legs.