We have always had some really, really good hunts around thanksgiving and Christmas. Some of the best shoots I've ever been on we're around Christmas. When I go back home to NC for the holidays, we always try have a couple of hunts. Most of friends I grew up with are farmers so we keep an eye on the fields in the winter. Last year we hunted a harvested sunflower field the day after Christmas and shot several limits. To this day, probably the most memorable dove hunt I've ever been on was a Christmas Eve morning hunt. There was 20 shooters and we were all limited out in 2 hrs.
The biggest difference in late season birds is that fronts and temp changes can really affect your bird numbers. If you have birds when it's cold, then they should hang around, but if you have a lot of birds and its 55 degrees,the next cold front will push them south