first of all just because it's after the 1st of the year doesn't mean your colony is either in need of food or willing to break winter cluster to get it. depends on a number of conditions. Whats the daily temperatures been of late. much below 45 they won't break cluster unless pressed to by hunger. ample honey stores-if they have ample honey stored--then they have no need of outside sources to have to break cluster process and store. Be assured they will get it as the breeding season starts in ernest, but until they see the need to use it they will use stores closer to cluster.
I use fondant. As Barry mentioned, I think fondant is more of an emergancy type feed. Unless the hive is weak, and they starve out "in place", most hives will go through the normal motions of using their stores, and usually end up up under the inner cover, where they are trying to conserve energy. So I place the fondant on the inner cover hole and have had bees that normally would of starved, eat for months on a 25 pound block of fondant.
Bees actually use less stores than most think through the first half of winter. Once they start rearing brood, they will consume three times as much. That fondant will come in handy going forward.
In my area early March is when we start losing bees from starvation. Like Bjorn bee said, they use up there stores raising brood and not much comming in. I'm trying the mountain camp method for the first time on some off my lighter hives, and it seems to be working good. Jack