Abstraction in photography is, I (currently) think, different from abstraction in other arts. That's sort of a duh, right? But the point is that an abstract photograph is ultimately a photograph OF something that is real and exists. We, the viewer, have to contend with that. An abstract painting might or might not represent something real, but we don't have to contend with the issue of it actually being something -- and we don't know WHAT.
This photograph suffers from that, but also suffers from, I think, the fact that the gradation from light to dark follows a sort of weird U-shaped path. Not only are we irritated that we don't know what it is, following gradations of light and dark goes nowhere, following lines (however weak they are) also goes nowhere. The natural high point of the picture, that birdlike shadow, is isolated and cut off from everything else. It's obvious, it's not like we have to hunt for the damn thing, but nothing in the picture seems to particularly support it. Everything else is just a jumble of actively distracting stuff.