Today was windy, but pretty warm, so we finally decided to open up the beehive and see how our diminished colony was faring. We found complete devastation. Every bee had died, some in clusters; many were inside comb cells, with only their backs sticking out, making a beautiful pattern. We found no signs of mites. The bees looked fine, just lifeless, so our assumption is that they simply froze to death. We knew their numbers were so few they were unlikely to survive the winter—their survival depends on their ability to keep warm, and they need a large population to generate warmth.
We went through the frames, examining each one carefully. A lot of honey is still left, which we will extract. Some of the frames have a gray film on them that we will attempt to identify.
It is a sad day. We let our bees down. The moment we knew their population had grown too large we should have given them more space by adding another super. Instead they swarmed. Then we were unsuccessful with the new queens we introduced to both the hives (the queens were accepted, but they never produced enough brood). As their numbers dropped, so did their chances for survival.
Bees have a fairly short life and they spend it working hard, with the sole focus of perpetuating their colony. They died a little prematurely, and failed to produce the next generation. This failure was ours as well. We will try again, ordering new bees, building new frames (in case there is any disease in the ones we have). And we will try to learn from our mistakes so in some way our lost hives will benefit future generations.