What Bird Is That Forum

Amar Ayyash has looked at this bird and said it likely was a “porky” Thayer’s but the structure is off to him. I definitely agree and will leave it as larus sp. but was curious what y’all’s thoughts are. https://ebird.org/checklist/S290216611

When I saw photos of this bird, I thought it was likely a Cook Inlet (AHGU x GWGU), though given the location, I could see it as a Thayer's. The pattering on the primaries seems better for a cook, as does the overall structure.

Larus sp. is a perfect place for this bird.

Some were saying the p9 mirror was good for Thayer’s but not Cook Inlet which is one of the reasons I am leaning away from that

I could certainly see that, the p9 mirror is rather large for a typical Cook Inlet. That hybrid mix is so variable, though, and I'm not sure where exactly the limits lie on what they can look like.

Yeah, theoretically if neither parent has large p9s the conclusion is that the young would not show that either but not sure that holds up in reality or not. Bird is still around but more pics aren’t really gonna help at this point