Note: If you've been considering keeping bees and wanted to start this year, you'll need to order packages for delivery in late March or April in the next few weeks. Most of the local bee supply companies sell out of packages. Once that order is placed, purchasing, assembly and painting of your hives is a great rainy day project.
Bees don't hibernate over the winter; they huddle in their hives, sending a few workers out to check conditions from time to time, eating honey and waiting until it's flying weather. These bees start flying at about 45 degrees, and at 55 degrees most of the workers are out searching.
Tree pollen is what's there at this time of year, and I suspect there's some nectar, too, but I don't know what kind. I'm just seeing bees return to the hive without pollen on their legs. Could be that they are just bringing water back, too, or trace minerals of some sort.
For my bees this year I chose to leave the honey on the hive; I didn't know how much they'd need to over-winter, and they'll keep the honey in perfect condition. When the nectar starts flowing in earnest, april-may-june I'll pull the remaining honey off and harvest, leaving empty comb for the bees to refill.
I purchased four packages last winter and 3 have made it this far. While I'm not happy that I lost one, you do lose colonies from time to time. The goal is to lose as few as possible.