pedini, the lack of setting/ground was a very deliberate choice. in the beginning i was experimenting with having some streets laid out in a lighter color, but the whole scene started to look too grid-like. i found that leaving the buildings floating in space mirrored the shape of the birds in flight. it looks almost as if the whole cityscape is taking to wing with the birds and flying out of the grave. that's my (admittedly biased) two cents. thanks!
totally subjective - but I respectfully disagree with Pedini here, the neg space is part of the charm/restraint/strength for me... I also love its play with the omitted (needless) outline of the flock - adds depth and texture. My tuppence (probably overpriced)