New birds

Went out yesterday afternoon and sat in the field until dark with many a flock flying over. A lot of times the geese will fly over at tree top level and not shy away very easily from my set up but they sure did this time. Is this a sign of new birds in the area or are the resident birds getting wary of blinds and decoys after being shot at a few times? I took a shot but it was a clean miss. I'm afraid of the cold weather will freeze the ponds and lakes in the area and mark the end of hunting.