calling can be done at any time but the status of the rut will determine what calls to use.generaly in early season non aggressive contact calls should be used,soft grunts and bleats.when the rut get cooking more aggressive calls are in order,aggressive buck grunts,tending doe grunts,clicking etc,etc.effectivness of rattling is directly proportional to the buck to doe ratio.the perfect buck to doe ratio is 3 buck to one doe.if its the other way around rattling will be much less effective if effective at all.