All nice, but my order of preference is 4,3,2,1.
The reason there is the head angles of the birds. Number 4 has dynamic wing positions for both as well as a good look at the faces. The left hand bird is angles slightly away but not enough to be a deal breaker.
Compare that to the first 2 where we're struggling to get as good a look at the faces of both birds, who whilst there is good action going on, at leas one bird is hiding away each time. In fact if there was a little more room the second would have been great for a single shot of the left hand bird.
Like I say, they are good shots, but when you're looking to pick your best one, these are the little things that count
Mike