[nature] Do robins and other common birds fly south in winter?

[deckeda]

Apparently not, but what DO they do? Yesterday morning was unseasonably warm and some kinda birds could be heard in the neighborhood en masse as if to say, "Spring is here!" and today I went outside and there's about 6 robins and a bluejay on the lawn angling for worms or whatever. It did rain but c'mon.