Two days ago it got up in the high 40's here in Indiana. I went over and checked my 9 hives. 6 of these 9 are swarms I caught last year (2016). At first I was nervous because I was expecting them to really be flying since it had been below freezing the week before and just now climbing back up. When I saw no bees flying I thought all of them were dead. The first one I checked was actually dead, it was a swarm from 2 years ago that never really did anything. Thy stayed alive but didn't ever produce, and they were my most aggressive hive. I popped the lids on all the other one by one and either heard bees buzzing in them or saw some bees flying out after I disturbed them a little. This week is supposed to be warmer then average here.
The hive that was dead was 2 8 frame deeps and the top box was still very heavy so they didn't starve to death. Not sure what got them but I did a 3 step OAV late this fall. I didn't have time to go through the hive yet but as I set the two boxes in the back of a my truck it looked like a large number of the dead bees were still in the bottom of the hive. Last year the only hive I lost over the winter was completely empty this spring when I checked on it. No dead bees around.
I spoke to two other nearby beeks who saw the same thing, no bees flying that day and both were nervous. One beek said two weeks ago it warmed up to 50 degrees and the bees were out all over the place. They must have all got their bathroom breaks in then and didn't need to come out this week.
I am curious during the winter if they know there is nothing to forage and they have been out to crap already will they stay in the hive during some warm spells to conserve energy?