So, one of the problems that us northern beekeepers face overwinter is trying to determine if a hive is still alive or not in the middle of winter without disturbing it too much. It isn't advisable to just open it up. I have tried peering into the entrance with a flashlight to see the cluster, trying to figure out what the relationship is to the number of dead bees that a living hive should be expelling each week, etc. If it is cold enough though - there is another way. I think that I might have stumbled on another strategy! This photo is of the upper entrance of a nuc that I know is alive today (12 December 2010). I know this because I can look through the entrance with a light and see the cluster, happily 'pulsating' away. [attachment=2:1nt8fo19]Alive.jpg[/attachment:1nt8fo19] This photo is of a nuc that I know has died. Again, I can see the cluster - and it is (sadly) not moving. [attachment=1:1nt8fo19]Dead.jpg[/attachment:1nt8fo19] This final photo is of the upper entrance of a nuc that I just wasn't sure about. I can't see the cluster, it hasn't produced any dead bees in front and I don't want to open it up to check. [attachment=0:1nt8fo19]Yeah!.jpg[/attachment:1nt8fo19] On cold, dry days - heat and moisture from the (living) cluster produces frost on the upper entrances. Looks like, so far so good!