Once the birds bust you, the game is up. I've tried scattering them and then calling them back, but I've never had much luck. Best thing, in my opinion, you can do this time of year is to watch and pattern them. Winter flocked birds are really easier to pattern then spring birds. They seem to follow the same schedule and pattern on a consistent basis. So, with that in mind, when you find a flock, keep your distance and try to put a pattern on what they do. Usually this means watching one day, or morning, and actually trying for the shot the next day or that afternoon. Can't over emphasize how important it is to stay hidden and not move when the birds are around. Nothing worse than sitting all morning waiting to ambush a flock only to have them bust you when you did nothing more than turn your head, or scratch your nose, or lift a leg to a more comfortable position. They aren't like deer or elk, once they bust you they're gone-no stopping 50 yards away and looking back over a shoulder or anything like that. A good pair of binoculars and a lot of patience are more important this time of year than calls and decoys.