The man who keeps bees at my small farm found that two seemingly strong
hives had suddenly died in early spring. They were both full of honey
with
dead bees between the frames of the top super, so it wasn't starvation;
and
the hives were adequately insulated and sealed with only small openings
for
the bees to get out and relieve themselves on warmer, sunny days. I had
examined the hives in late January and found them strong and apparently
healthy.
His explanation: during the warm spell in January (we almost always have
one here in NW Indiana) the bees broke cluster to leave the hive to
relieve
themselves and then reentered the hives and fed. After this warm spell
the
temperature and weather changed drastically with zero and single-digit
temperatures for nearly two weeks. He contends that the bees did not
return
to their usual winter cluster around the queen -- "broke cluster!" -- and
all froze to death.
I have never heard of this; what do some of you know about "breaking
cluster"?