Excellent use of negative space. I like the composition and the colors. I wish there was a bit more contrast to darken the birds a bit, but that doesn't detract from a solid 9.
Perhaps the space at the top was kept intentionally but I would much prefer to have it some of it cropped off to bring more attention to the 'V-shape' form of the birds as I feel that the birds inthe middle of the image are the real subjects when I find the "V" is much more interesting.
I can't put my finger on it. I think maybe if the negative space was ahead of them, in the direction they are facing, that might work better. Nice catch though.
Very nice. Definitely a great use of negative space. The blue of the sky is a little unappealing on my monitor - not quite sure why. Makes me want to see this in black and white and see if that would make it more dramatic.