Fall shuffle is in my experience more a term used for bobwhite quail and ruffed grouse. Though I can see some relation to other species it is a common term for a specific behavior of bobwhites and ruffs,and describes a time in the fall of the year, when family brood coveys breakup and and members set off sometimes quite a distance and join other birds eventually forming other coveys of birds from unrelated broods. It is assumed that the reasons are expansion of territories, broadening of the gene pool. Nobody really knows. This is a poor explanation, but there is a lot of info out there, research. it generally occurs prior to hunting season, but sometimes for who knows what reason it happens late. Result is quail disappear from typical haunts, only to reappear later, in the expected places. Shuffling of pheasants as described here above has more to do with weather related short range migration, to prefered winter cover and feed, sharptails do this as well.