I would not count a buck going nocturnal as evolution. In the true definition of evolution, I don't think that going nocturnal could count because it is a behavior exhibited by a few individuals of a the species, not necesarily something that is being passed on. It would be like breaking a leg, having a child, and that childs leg is broken because the parent's leg was broken during pregnancy. Acquired traits (learned behavior) is not something that is passed on, it is not encoded in the genes.