No. All species of birds do not migrate south. Some birds, northern finches, for example, may migrate east and/or west, in search of food in winter. Many birds do not migrate at all. The formation of birds that you saw were probably blackbirds...red-winged and other blackbirds, cowbirds, or possibly European starlings...which form large flocks during migration periods. They will probably end up farther south for the winter. GHH
