I wouldn't know what's in the birds mouth. I like both shots of the gull in flight, but the one with its wings wide open allows the viewer to view the bird's plumage.
If the question is which photo is best I'd go with #4. I think it's the contrast that I like. That first one with gray sky and a grayish brown bird just doesn't do it or me. That being said 2 and 3 are a toss up for me. Nothing technical simply personal preference.
As far as seagull images go these are pretty normal and slightly less than average. These birds are so easy to capture, only spectacular shots should be expected.