what scott said! i also use a one gallon pail of 2:1 if need be. if bees don't take the syrup down, it could be for a number of reasons; they don't need it, temps are too cold and/or sugar syrup is too cold to take down. i also use a shim feeder, and place winter patties, fondant or sugar cakes/candy on. just extra insurance.
if your hives are heavy you may not need to feed syrup, if you do, now is the time. fondant/sugar can be added later......after syrup is removed.