From everything I have read buck survival rate is well below that of does from the first year on up. I don't recall exactly why it was lower the first year (I think it has something to do with growing more boneand therefore they areunable to store as much fat as a doe fawn), but every year after that is relatively self-explanatory (expendature during the rut). Add that to the fact that in general hunters will shoot a 1.5 year old buck over any doe and there you go.