That Looks Odd

Gull 1: That looks odd.
Gull 2: What does?
Gull 1: There. It looks like that Redshank is swimming.
Gull 2: You know, I think you're right.
Gull 1: Don't think I've seen that before.
Gull 2: Me neither.

I gather that this sort of behaviour is more frequent in Spotted Redshanks but pretty sure this is just a Common Redshank (see extra).