Contrary to popular belief, honeybees do not hibernate. They stay active all winter long. The hive must stay warm, the bees must eat and feed their queen, and they have to defend against other animals seeking a warm place.
I did a few different things this winter compared to the past winters, and I hope they are helping. The last couple winters have seen the colony survive winter without a queen. To keep the queen near a food source, I moved the queen excluder all the way to the top of the hive this year. I set quart bags of syrup in the top box, so the excluder is below it. In this way, workers and the queen can get close to the food without leaving the hive.
I know the bees are active because I can see them leaving the hive entrance from my windows. When the temps are warm, say over 40 degrees, they’ll come out and take a potty break. Similar to other animals (dogs come to mind), honeybees will not soil their homes if they can avoid it. They “hold it” until they can “go” outside. Some die from holding it too long. According to Winter World by Bernd Heinrich, some may die as on a ‘kamikazi’ mission — one leaves as a safety test. If she lives, then everyone can safely go outside; if she dies, then no one leaves the hive.
Looking outside the hive, I see the snowy ground is lightly littered with bee corpses. The photo above contains one of them. A couple are still on top of the snow. Since bee bodies are dark, they heat and melt the snow around until it looks like what you see here.