A tilted horizon is not wrong per se, but I believe it should be used carefully and for a specific purpose, for example to increase drama, to compliment an unusual perpsective, or to compliment at theme such as abstract shapes. In this case, to me, it brings nothing and indeed detracts from the viewing experience. Perhaps if the fishing rod had been held at a digonal angle that would have become perpendicular it might have helped tie the photo together. For this reason I have only given a 3, but I do hope you took some 'straight' shots as well as this is otherwise a super scene.
it's interesting to note how the fishing poles seem to be leading those clouds in the background. cool shot, love the bird. . .i just wonder if it would be better without the extreme tilt.