There's a neat evolutionary trick or two that enables colonies of honey bees to overwinter, and it isn't just the bees ability to cluster for days (weeks) on end when it's cold. Clustering, don't forget, is essentially an emergency measure to protect the queen and to keep her warm and safe.
Bees cluster when they collect around the queen whilst they're searching for a new place to live after swarming from the parent colony, and they will cluster when the inside of their nest is too cold for them to be able to safely walk around on their own without freezing to death. It's a pretty dangerous thing to do though, because a clustered winter colony will always settle over brood – the future of the colony - and can starve to death a mere inch or so away from food, which is why choosing the right nesting site after swarming is pretty important,
